U.S. patent application number 16/601563 was filed with the patent office on 2021-04-15 for free-riding node identification for blockchain.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Dushyant K. Behl, Palanivel Andiappan Kodeswaran, Sayandeep Sen.
Application Number | 20210109776 16/601563 |
Document ID | / |
Family ID | 1000005490278 |
Filed Date | 2021-04-15 |
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United States Patent
Application |
20210109776 |
Kind Code |
A1 |
Behl; Dushyant K. ; et
al. |
April 15, 2021 |
FREE-RIDING NODE IDENTIFICATION FOR BLOCKCHAIN
Abstract
An example operation may include one or more of receiving system
calls captured from a plurality of peer nodes of a blockchain that
occurred within a predetermined period of time, determining a
subset of system calls among the received system calls that
correspond to a blockchain process performed during the
predetermined period of time, detecting a free-riding peer node
from among the plurality of peer nodes based on the identified
subset of system calls with respect to system calls of the
free-riding peer node within the predetermined period of time, and
storing an indicator of the free-riding peer node.
Inventors: |
Behl; Dushyant K.;
(BANGALORE, IN) ; Sen; Sayandeep; (Bangalore,
IN) ; Kodeswaran; Palanivel Andiappan; (Bangalore,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
1000005490278 |
Appl. No.: |
16/601563 |
Filed: |
October 14, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 67/1097 20130101;
H04L 41/06 20130101; G06F 9/451 20180201; G06F 9/466 20130101; G06F
16/2379 20190101; G06F 16/2365 20190101 |
International
Class: |
G06F 9/46 20060101
G06F009/46; G06F 16/23 20060101 G06F016/23; G06F 9/451 20060101
G06F009/451; H04L 29/08 20060101 H04L029/08; H04L 12/24 20060101
H04L012/24 |
Claims
1. An apparatus comprising: a network interface configured to
collect system calls captured from a plurality of peer nodes of a
blockchain that occurred within a predetermined period of time; and
a processor configured to determine a subset of system calls among
the received system calls that correspond to a blockchain process
performed within the predetermined period of time, detect a
free-riding peer node from among the plurality of peer nodes based
on the identified subset of system calls with respect to system
calls of the free-riding peer node within the predetermined period
of time, and store an indicator of the free-riding peer node.
2. The apparatus of claim 1, wherein the system calls are
independently captured by the plurality of peer nodes based on a
trace of chaincode that commonly runs on the plurality of peer
nodes.
3. The apparatus of claim 1, wherein the processor determines a
subset of system calls that were performed by more than a
predetermined number of the peer nodes within the predetermined
period of time.
4. The apparatus of claim 1, wherein the processor is configured to
generate a map which identifies how many peer nodes performed each
system call among the system calls, and identify the subset of
system calls based on the map.
5. The apparatus of claim 4, wherein the processor identifies
system calls that were performed by a majority of the peer nodes,
as the subset of system calls.
6. The apparatus of claim 1, wherein the processor is further
configured to generate and output an alarm via a user interface, in
response to detection of the free-riding peer node.
7. The apparatus of claim 1, wherein the processor detects the free
riding peer node in response to detection of a failure by the
free-riding peer node to perform a system call from among the
identified subset of system calls.
8. The apparatus of claim 1, wherein the processor detects the
free-riding peer node via misbehavior identification chaincode.
9. A method comprising: receiving system calls captured from a
plurality of peer nodes of a blockchain that occurred within a
predetermined period of time; determining a subset of system calls
among the received system calls that correspond to a blockchain
process performed during the predetermined period of time;
detecting a free-riding peer node from among the plurality of peer
nodes based on the identified subset of system calls with respect
to system calls of the free-riding peer node within the
predetermined period of time; and storing an indicator of the
free-riding peer node.
10. The method of claim 9, wherein the system calls are
independently captured by the plurality of peer nodes based on a
trace of chaincode that commonly runs on the plurality of peer
nodes.
11. The method of claim 9, wherein the determining comprises
determining a subset of system calls that were performed by more
than a predetermined number of the peer nodes within the
predetermined period of time.
12. The method of claim 9, wherein the determining comprises
generating a map which identifies how many peer nodes performed
each system call among the system calls, and identifying the subset
of system calls based on the map.
13. The method of claim 12, wherein the identifying comprises
identifying system calls that were performed by a majority of the
peer nodes, as the subset of system calls.
14. The method of claim 9, further comprising generating and
displaying an alarm via a user interface, in response to detecting
the free-riding peer node.
15. The method of claim 9, wherein the detecting comprises
detecting the existence of the free riding peer node in response to
detecting a failure by the free-riding peer node to perform a
system call from among the identified subset of system calls.
16. The method of claim 9, wherein the detecting the free-riding
peer node is performed via misbehavior identification
chaincode.
17. A non-transitory computer-readable medium comprising
instructions, that when read by a processor, cause the processor to
perform a method comprising: receiving system calls captured from a
plurality of peer nodes of a blockchain that occurred within a
predetermined period of time; determining a subset of system calls
among the received system calls that correspond to a blockchain
process performed during the predetermined period of time;
detecting a free-riding peer node from among the plurality of peer
nodes based on the identified subset of system calls with respect
to system calls of the free-riding peer node within the
predetermined period of time; and storing an indicator of the
free-riding peer node.
18. The non-transitory computer-readable medium of claim 17,
wherein the system calls are independently captured by the
plurality of peer nodes based on a trace of chaincode that commonly
runs on the plurality of peer nodes.
19. The non-transitory computer-readable medium of claim 17,
wherein the determining comprises determining a subset of system
calls that were performed by more than a predetermined number of
the peer nodes within the predetermined period of time.
20. The non-transitory computer-readable medium of claim 17,
wherein the determining comprises generating a map which identifies
how many peer nodes performed each system call among the system
calls, and identifying the subset of system calls based on the map.
Description
TECHNICAL FIELD
[0001] This application generally relates to a system for storing
data via blockchain, and more particularly, to a system which can
identify free-riding nodes within a blockchain network that are not
contributing as expected.
BACKGROUND
[0002] A centralized database stores and maintains data in a single
database (e.g., a database server) at one location. A centralized
database is easy to manage, maintain, and control, especially for
purposes of security because of its single location. However, a
centralized database suffers from significant drawbacks. For
example, a centralized database has a single point of failure.
Therefore, data that is unexpectedly lost is very difficult to
retrieve other than through manual operation from back-up storage.
In addition, a centralized database can be highly dependent on
network connectivity. Furthermore, a centralized database may only
provide limited access to data when only one copy of the data is
maintained by the database.
[0003] Recently, organizations have been turning to blockchain as
an improved storage system over a traditional database. Blockchain
offers data redundancy, no single central authority, multiple nodes
of access, an immutable ledger, and the like. Another benefit of
blockchain is the requirement that transactions be approved fairly
through endorsement and consensus. Thus, untrusting parties can
interact and share in the management of the blockchain. In
particular, these untrusting parties typically manage nodes which
undertake roles such as storage of the blockchain, endorsement of
transactions, and the like.
[0004] Endorsing peer nodes within a blockchain network are
responsible for verifying a transaction proposal from a client
before it can be stored on the blockchain. The endorsing peer may
receive a transaction proposal, verify the client signature, and
execute a chaincode function to initiate the transaction. If the
transaction executes successfully, a proposal response may be sent
back to the client along with an endorsement signature. When the
client receives a predetermined number of endorsement signatures
(e.g., from at least half of the endorser nodes, etc.), transaction
is approved and will be stored on the blockchain. Endorsing nodes
are often compensated for their role due to the computation
necessary, security to be maintained, etc. However, a free-riding
node may exist among the endorsing nodes. The free-riding node does
not perform all of its required duties as an endorser. The failure
can go unnoticed (disguised). For example, the free-riding
endorsing node may simply send an approval signature, use another
node's read-write set, etc., without having to verify the work that
was performed.
[0005] As such, what is needed is a solution that can identify
free-riding nodes within a blockchain and overcome these drawbacks
and limitations.
SUMMARY
[0006] One example embodiment provides a system that includes one
or more of a network interface configured to collect system calls
captured from a plurality of peer nodes of a blockchain that
occurred within a predetermined period of time, and a processor
configured to one or more of determine a subset of system calls
among the received system calls that correspond to a blockchain
process performed within the predetermined period of time, detect a
free-riding peer node from among the plurality of peer nodes based
on the identified subset of system calls with respect to system
calls of the free-riding peer node within the predetermined period
of time, and store an indicator of the free-riding peer node.
[0007] Another example embodiment provides a method that includes
one or more of receiving system calls captured from a plurality of
peer nodes of a blockchain that occurred within a predetermined
period of time, determining a subset of system calls among the
received system calls that correspond to a blockchain process
performed during the predetermined period of time, detecting a
free-riding peer node from among the plurality of peer nodes based
on the identified subset of system calls with respect to system
calls of the free-riding peer node within the predetermined period
of time, and storing an indicator of the free-riding peer node.
[0008] A further example embodiment provides a non-transitory
computer readable medium comprising instructions, that when read by
a processor, cause the processor to perform one or more of
receiving system calls captured from a plurality of peer nodes of a
blockchain that occurred within a predetermined period of time,
determining a subset of system calls among the received system
calls that correspond to a blockchain process performed during the
predetermined period of time, detecting a free-riding peer node
from among the plurality of peer nodes based on the identified
subset of system calls with respect to system calls of the
free-riding peer node within the predetermined period of time, and
storing an indicator of the free-riding peer node.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a diagram illustrating a system for identifying
free-riding nodes within a blockchain network according to example
embodiments.
[0010] FIG. 2A is a diagram illustrating an example blockchain
architecture configuration, according to example embodiments.
[0011] FIG. 2B is a diagram illustrating a blockchain transactional
flow among nodes, according to example embodiments.
[0012] FIG. 3A is a diagram illustrating a permissioned network,
according to example embodiments.
[0013] FIG. 3B is a diagram illustrating another permissioned
network, according to example embodiments.
[0014] FIG. 3C is a diagram illustrating a permissionless network,
according to example embodiments.
[0015] FIG. 4A is a diagram illustrating an architecture of peer
node with a trace module running therein according to example
embodiments.
[0016] FIG. 4B is a diagram illustrating a process of generating a
system call map from system calls of a plurality of nodes according
to example embodiments.
[0017] FIG. 4C is a diagram illustrating a process of detecting a
free-riding node based on the system call map according to example
embodiments.
[0018] FIG. 5 is a diagram illustrating a method of identifying a
free-riding node within a blockchain network according to example
embodiments.
[0019] FIG. 6A is a diagram illustrating an example system
configured to perform one or more operations described herein,
according to example embodiments.
[0020] FIG. 6B is a diagram illustrating another example system
configured to perform one or more operations described herein,
according to example embodiments.
[0021] FIG. 6C is a diagram illustrating a further example system
configured to utilize a smart contract, according to example
embodiments.
[0022] FIG. 6D is a diagram illustrating yet another example system
configured to utilize a blockchain, according to example
embodiments.
[0023] FIG. 7A is a diagram illustrating a process of a new block
being added to a distributed ledger, according to example
embodiments.
[0024] FIG. 7B is a diagram illustrating data contents of a new
data block, according to example embodiments.
[0025] FIG. 7C is a diagram illustrating a blockchain for digital
content, according to example embodiments.
[0026] FIG. 7D is a diagram illustrating a block which may
represent the structure of blocks in the blockchain, according to
example embodiments.
[0027] FIG. 8A is a diagram illustrating an example blockchain
which stores machine learning (artificial intelligence) data,
according to example embodiments.
[0028] FIG. 8B is a diagram illustrating an example quantum-secure
blockchain, according to example embodiments.
[0029] FIG. 9 is a diagram illustrating an example system that
supports one or more of the example embodiments.
DETAILED DESCRIPTION
[0030] It will be readily understood that the instant components,
as generally described and illustrated in the figures herein, may
be arranged and designed in a wide variety of different
configurations. Thus, the following detailed description of the
embodiments of at least one of a method, apparatus, non-transitory
computer readable medium and system, as represented in the attached
figures, is not intended to limit the scope of the application as
claimed but is merely representative of selected embodiments.
[0031] The instant features, structures, or characteristics as
described throughout this specification may be combined or removed
in any suitable manner in one or more embodiments. For example, the
usage of the phrases "example embodiments", "some embodiments", or
other similar language, throughout this specification refers to the
fact that a particular feature, structure, or characteristic
described in connection with the embodiment may be included in at
least one embodiment. Thus, appearances of the phrases "example
embodiments", "in some embodiments", "in other embodiments", or
other similar language, throughout this specification do not
necessarily all refer to the same group of embodiments, and the
described features, structures, or characteristics may be combined
or removed in any suitable manner in one or more embodiments.
Further, in the diagrams, any connection between elements can
permit one-way and/or two-way communication even if the depicted
connection is a one-way or two-way arrow. Also, any device depicted
in the drawings can be a different device. For example, if a mobile
device is shown sending information, a wired device could also be
used to send the information.
[0032] In addition, while the term "message" may have been used in
the description of embodiments, the application may be applied to
many types of networks and data. Furthermore, while certain types
of connections, messages, and signaling may be depicted in
exemplary embodiments, the application is not limited to a certain
type of connection, message, and signaling.
[0033] Example embodiments provide methods, systems, components,
non-transitory computer readable media, devices, and/or networks,
which identify free-riding nodes within a blockchain network.
[0034] In one embodiment the system deploys and configures a
decentralized database (such as a blockchain) that is a distributed
storage system, which includes multiple nodes that communicate with
each other. The decentralized database includes an append-only
immutable data structure resembling a distributed ledger capable of
maintaining records between mutually untrusted parties. The
untrusted parties are referred to herein as peers or peer nodes.
Each peer maintains a copy of the database records and no single
peer can modify the database records without a consensus being
reached among the distributed peers. For example, the peers may
execute a consensus protocol to validate blockchain storage
transactions, group the storage transactions into blocks, and build
a hash chain over the blocks. This process forms the ledger by
ordering the storage transactions, as is necessary, for
consistency. In various embodiments, a permissioned and/or a
permissionless blockchain can be used. In a public or
permission-less blockchain, anyone can participate without a
specific identity. Public blockchains can involve native
cryptocurrency and use consensus based on various protocols such as
Proof of Work (PoW). On the other hand, a permissioned blockchain
database provides secure interactions among a group of entities
which share a common goal but which do not fully trust one another,
such as businesses that exchange funds, goods, information, and the
like.
[0035] The blockchain may operate arbitrary, programmable logic,
tailored to a decentralized storage scheme and referred to as
"smart contracts" or "chaincodes." In some cases, specialized
chaincodes may exist for management functions and parameters which
are referred to as system chaincode. The application can further
utilize smart contracts that are trusted distributed applications
which leverage tamper-proof properties of the blockchain database
and an underlying agreement between nodes, which is referred to as
an endorsement or endorsement policy. Blockchain transactions
associated with this application can be "endorsed" before being
committed to the blockchain while transactions, which are not
endorsed, are disregarded. An endorsement policy allows chaincode
to specify endorsers for a transaction in the form of a set of peer
nodes that are necessary for endorsement. When a client sends the
transaction to the peers specified in the endorsement policy, the
transaction is executed to validate the transaction. After
validation, the transactions enter an ordering phase in which a
consensus protocol is used to produce an ordered sequence of
endorsed transactions grouped into blocks.
[0036] The blockchain can include nodes configured therein that are
the communication entities of the blockchain system. A "node" may
perform a logical function in the sense that multiple nodes of
different types can run on the same physical server. Nodes are
grouped in trust domains and are associated with logical entities
that control them in various ways. Nodes may include different
types, such as a client or submitting-client node which submits a
transaction-invocation to an endorser (e.g., peer), and broadcasts
transaction-proposals to an ordering service (e.g., ordering node).
Another type of node is a peer node which can receive client
submitted transactions, commit the transactions and maintain a
state and a copy of the ledger of blockchain transactions. Peers
can also have the role of an endorser, although it is not a
requirement. An ordering-service-node or orderer is a node running
the communication service for all nodes, and which implements a
delivery guarantee, such as a broadcast to each of the peer nodes
in the system when committing transactions and modifying a world
state of the blockchain, which is another name for the initial
blockchain transaction which normally includes control and setup
information.
[0037] The blockchain may include a ledger that is a sequenced,
tamper-resistant record of all state transitions of a blockchain.
State transitions may result from chaincode invocations (i.e.,
transactions) submitted by participating parties (e.g., client
nodes, ordering nodes, endorser nodes, peer nodes, etc.). Each
participating party (such as a peer node) can maintain a copy of
the ledger. A transaction may result in a set of asset key-value
pairs being committed to the ledger as one or more operands, such
as creates, updates, deletes, and the like. The ledger includes a
blockchain (also referred to as a chain) which is used to store an
immutable, sequenced record in blocks. The ledger also includes a
state database which maintains a current state of the
blockchain.
[0038] The chain (of the blockchain) is a transaction log which is
structured as hash-linked blocks, and each block contains a
sequence of N transactions where N is equal to or greater than one.
The block header includes a hash of the block's transactions, as
well as a hash of the prior block's header. In this way, all
transactions on the ledger may be sequenced and cryptographically
linked together. Accordingly, it is not possible to tamper with the
ledger data without breaking the hash links. A hash of a most
recently added blockchain block represents every transaction on the
chain that has come before it, making it possible to ensure that
all peer nodes are in a consistent and trusted state. The chain may
be stored on a peer node file system (i.e., local, attached
storage, cloud, etc.), efficiently supporting the append-only
nature of the blockchain workload.
[0039] The current state of the immutable ledger represents the
latest values for all keys that are included in the chain
transaction log. Since the current state represents the latest key
values known to a channel, it is sometimes referred to as a world
state. Chaincode invocations execute transactions against the
current state data of the ledger. To make these chaincode
interactions efficient, the latest values of the keys may be stored
in a state database. The state database may be simply an indexed
view into the chain's transaction log, it can therefore be
regenerated from the chain at any time. The state database may
automatically be recovered (or generated if needed) upon peer node
startup, and before transactions are accepted.
[0040] According to various embodiments, a free riding peer node
that is not properly contributing the blockchain network can be
identified through tracking of system calls. Within a permissioned
blockchain network, peer nodes may be required to install and
execute a trace module which captures system calls between
chaincode running on an endorsing peer node and an operating system
of the peer node. Meanwhile, a trusted entity (e.g., a blockchain
administrator, a pre-approved peer node, an arbitrator node, a
pre-approved service, etc.) may execute a free-rider detection
module (e.g., chaincode) which receives the system calls from the
endorsing peer nodes. Here, the trusted entity may communicate with
a trusted module stored on the endorsing peer nodes to ensure that
the node is running the correct trace module.
[0041] The free-rider detection module may receive the system calls
and identify system calls that are commonly performed among the
endorsing nodes (e.g., by a majority or some other predetermined
amount). The free-rider detection module may map the system calls
to a map and identify a set of system calls that were necessary to
perform the endorsement process from the map. Based on the set of
required system calls, the free-rider detection module can identify
an endorser node (from its own system calls) which did not perform
one or more of the required system calls, and label the node as a
free-riding node. Furthermore, the free-rider detection module may
output a warning or an alert thereby providing a mechanism by which
a free-riding peer node is caught.
[0042] Blockchain is a replicated execution system where different
subsets of actors (e.g., endorsing peer nodes for a given
chaincode) perform that same functionality across the entire
blockchain network. By dynamically collecting evidence of task
computation (such as endorsement) from all endorsing peer nodes,
and comparing them against each other, the system can predict
misbehavior by any dishonest peer node. The example embodiments may
be implemented within a peer as a service (PAAS) system for
permissioned blockchain where participants are monetarily
incentivized to run a peer to enable non peer owners to submit and
commit transactions to a permissioned blockchain.
[0043] Some benefits of the example embodiments include improved
security and prevention of fraud within a blockchain network,
especially permissioned networks which share revenue based on tasks
performed. The example embodiments enable fees to be fairly
distributed based on actual work performed (proven) even in a
situation where nodes may collude with one another (e.g., one
endorsing peer provides its read/write set to another endorsing
peer, etc.)
[0044] FIG. 1 illustrates a system 100 for identifying free-riding
nodes within a blockchain network according to example embodiments.
Referring to FIG. 1, the system 100 includes a plurality of
endorser peers 111-114 that are tasked with endorsing a transaction
from a client (not shown). Here, each of the endorsing peers
111-114 may include common chaincode which is executed during the
endorsement process. Thus, each of the endorsing peers 111-114
should perform the same system calls during the endorsement
process. In addition, the system 100 also includes an arbitrator
node 120. The arbitrator node 120 may be another peer node, a
blockchain administrator, a blockchain manager, etc. In some
embodiments, the arbitrator node 120 may also be one of the
endorser peer nodes, but is not required.
[0045] The arbitrator node 120 may access a blockchain ledger 122
that stores transactions endorsed by the endorser peers 111-114, to
identify the endorser peers 111-114. In other words, not all peer
nodes within a blockchain network need to or are required to
endorse a transaction. Furthermore, each chaincode functionality
may include a different group of endorser nodes. In addition, a
client may dynamically select a subset of endorser nodes. Thus, the
arbitrator node 120 may determine which endorser peers from among a
larger pool of nodes (possible endorsers) are associated with a
transaction from the blockchain ledger 122, which stores
endorsement information (chaincode, endorsement policy, node
identifiers, etc.)
[0046] According to various embodiments, a trace module may be
installed on each of the endorser nodes 111-114 which captures
system trace calls performed during a predetermined period of time.
The trace modules may independently collect the respective system
calls performed by the respective endorser peers 111-114, and
forward the collected system calls to a misbehavior detecting
chaincode implemented on the arbitrator node 120. The arbitrator
node 120, using the misbehavior detecting chaincode, may build a
system call map of a subset of the system calls collected from each
of the endorser peers 111-114.
[0047] For example, the arbitrator node 120 may build a map of
shared system calls for each of the endorser peers 111-114 based on
the system calls independently performed by the endorser peers
111-114, and identify which calls intersect among the different
endorser peers 111-114, as further described with respect to the
example of FIG. 4B. When a predetermined amount of the endorser
peers 111-114 perform the same system call within the period of
time, the system call may be determined as necessary for the
endorsement process. In other words, since all of the endorser
peers 111-114 should be executing the same chaincode, they should
likewise be executing the same system calls. Therefore, it can be
reasonably inferred that if a majority (or some other number) of
nodes perform the same system call, it is associated with the
endorsement process.
[0048] The built map may include only a set of system calls which
are determined to be part of the endorsement process. These system
calls should be performed by all of the endorser peer nodes, if
they are behaving appropriately. The arbitrator 120 may compare
each of the individual frequency maps of the respective endorser
peers 111-114 to the built system call map including the set of
system calls required for the endorsement process to identify any
endorser peers that are misbehaving (not performing all of the
necessary calls, etc.). In this example, endorser peer 114 is
identified as a free-riding peer because it is not performing the
necessary calls that the other endorser peers 111-113 are
performing. A warning or an alarm may be output to a display of the
arbitrator node 120, and to other nodes such as the endorser nodes
111-114, a client (not shown), or the like.
[0049] FIG. 2A illustrates a blockchain architecture configuration
200, according to example embodiments. Referring to FIG. 2A, the
blockchain architecture 200 may include certain blockchain
elements, for example, a group of blockchain nodes 202. The
blockchain nodes 202 may include one or more nodes 204-210 (these
four nodes are depicted by example only). These nodes participate
in a number of activities, such as blockchain transaction addition
and validation process (consensus). One or more of the blockchain
nodes 204-210 may endorse transactions based on endorsement policy
and may provide an ordering service for all blockchain nodes in the
architecture 200. A blockchain node may initiate a blockchain
authentication and seek to write to a blockchain immutable ledger
stored in blockchain layer 216, a copy of which may also be stored
on the underpinning physical infrastructure 214. The blockchain
configuration may include one or more applications 224 which are
linked to application programming interfaces (APIs) 222 to access
and execute stored program/application code 220 (e.g., chaincode,
smart contracts, etc.) which can be created according to a
customized configuration sought by participants and can maintain
their own state, control their own assets, and receive external
information. This can be deployed as a transaction and installed,
via appending to the distributed ledger, on all blockchain nodes
204-210.
[0050] The blockchain base or platform 212 may include various
layers of blockchain data, services (e.g., cryptographic trust
services, virtual execution environment, etc.), and underpinning
physical computer infrastructure that may be used to receive and
store new transactions and provide access to auditors which are
seeking to access data entries. The blockchain layer 216 may expose
an interface that provides access to the virtual execution
environment necessary to process the program code and engage the
physical infrastructure 214. Cryptographic trust services 218 may
be used to verify transactions such as asset exchange transactions
and keep information private.
[0051] The blockchain architecture configuration of FIG. 2A may
process and execute program/application code 220 via one or more
interfaces exposed, and services provided, by blockchain platform
212. The code 220 may control blockchain assets. For example, the
code 220 can store and transfer data, and may be executed by nodes
204-210 in the form of a smart contract and associated chaincode
with conditions or other code elements subject to its execution. As
a non-limiting example, smart contracts may be created to execute
reminders, updates, and/or other notifications subject to the
changes, updates, etc. The smart contracts can themselves be used
to identify rules associated with authorization and access
requirements and usage of the ledger. For example, a read set 226
may be processed by one or more processing entities (e.g., virtual
machines) included in the blockchain layer 216. A write set 228 may
include a result of processing the read set 226 via one or more
smart contracts. The physical infrastructure 214 may be utilized to
retrieve any of the data or information described herein.
[0052] A smart contract may be created via a high-level application
and programming language, and then written to a block in the
blockchain. The smart contract may include executable code which is
registered, stored, and/or replicated with a blockchain (e.g.,
distributed network of blockchain peers). A transaction is an
execution of the smart contract code which can be performed in
response to conditions associated with the smart contract being
satisfied. The executing of the smart contract may trigger a
trusted modification(s) to a state of a digital blockchain ledger.
The modification(s) to the blockchain ledger caused by the smart
contract execution may be automatically replicated throughout the
distributed network of blockchain peers through one or more
consensus protocols.
[0053] The smart contract may write data to the blockchain in the
format of key-value pairs. Furthermore, the smart contract code can
read the values stored in a blockchain and use them in application
operations. The smart contract code can write the output of various
logic operations into the blockchain. The code may be used to
create a temporary data structure in a virtual machine or other
computing platform. Data written to the blockchain can be public
and/or can be encrypted and maintained as private. The temporary
data that is used/generated by the smart contract is held in memory
by the supplied execution environment, then deleted once the data
needed for the blockchain is identified.
[0054] A chaincode may include the code interpretation of a smart
contract, with additional features. As described herein, the
chaincode may be program code deployed on a computing network,
where it is executed and validated by chain validators together
during a consensus process. The chaincode receives a hash and
retrieves from the blockchain a hash associated with the data
template created by use of a previously stored feature extractor.
If the hashes of the hash identifier and the hash created from the
stored identifier template data match, then the chaincode sends an
authorization key to the requested service. The chaincode may write
to the blockchain data associated with the cryptographic
details.
[0055] FIG. 2B illustrates an example of a blockchain transactional
flow 250 between nodes of the blockchain in accordance with an
example embodiment. Referring to FIG. 2B, the transaction flow may
include a transaction proposal 291 sent by an application client
node 260 to an endorsing peer node 281. The endorsing peer 281 may
verify the client signature and execute a chaincode function to
initiate the transaction. The output may include the chaincode
results, a set of key/value versions that were read in the
chaincode (read set), and the set of keys/values that were written
in chaincode (write set). The proposal response 292 is sent back to
the client 260 along with an endorsement signature, if approved.
The client 260 assembles the endorsements into a transaction
payload 293 and broadcasts it to an ordering service node 284. The
ordering service node 284 then delivers ordered transactions as
blocks to all peers 281-283 on a channel. Before committal to the
blockchain, each peer 281-283 may validate the transaction. For
example, the peers may check the endorsement policy to ensure that
the correct allotment of the specified peers have signed the
results and authenticated the signatures against the transaction
payload 293.
[0056] Referring again to FIG. 2B, the client node 260 initiates
the transaction 291 by constructing and sending a request to the
peer node 281, which is an endorser. The client 260 may include an
application leveraging a supported software development kit (SDK),
which utilizes an available API to generate a transaction proposal.
The proposal is a request to invoke a chaincode function so that
data can be read and/or written to the ledger (i.e., write new key
value pairs for the assets). The SDK may serve as a shim to package
the transaction proposal into a properly architected format (e.g.,
protocol buffer over a remote procedure call (RPC)) and take the
client's cryptographic credentials to produce a unique signature
for the transaction proposal.
[0057] In response, the endorsing peer node 281 may verify (a) that
the transaction proposal is well formed, (b) the transaction has
not been submitted already in the past (replay-attack protection),
(c) the signature is valid, and (d) that the submitter (client 260,
in the example) is properly authorized to perform the proposed
operation on that channel. The endorsing peer node 281 may take the
transaction proposal inputs as arguments to the invoked chaincode
function. The chaincode is then executed against a current state
database to produce transaction results including a response value,
read set, and write set. However, no updates are made to the ledger
at this point. In 292, the set of values, along with the endorsing
peer node's 281 signature is passed back as a proposal response 292
to the SDK of the client 260 which parses the payload for the
application to consume.
[0058] In response, the application of the client 260
inspects/verifies the endorsing peers signatures and compares the
proposal responses to determine if the proposal response is the
same. If the chaincode only queried the ledger, the application
would inspect the query response and would typically not submit the
transaction to the ordering node service 284. If the client
application intends to submit the transaction to the ordering node
service 284 to update the ledger, the application determines if the
specified endorsement policy has been fulfilled before submitting
(i.e., did all peer nodes necessary for the transaction endorse the
transaction). Here, the client may include only one of multiple
parties to the transaction. In this case, each client may have
their own endorsing node, and each endorsing node will need to
endorse the transaction. The architecture is such that even if an
application selects not to inspect responses or otherwise forwards
an unendorsed transaction, the endorsement policy will still be
enforced by peers and upheld at the commit validation phase.
[0059] After successful inspection, in step 293 the client 260
assembles endorsements into a transaction and broadcasts the
transaction proposal and response within a transaction message to
the ordering node 284. The transaction may contain the read/write
sets, the endorsing peers signatures and a channel ID. The ordering
node 284 does not need to inspect the entire content of a
transaction in order to perform its operation, instead the ordering
node 284 may simply receive transactions from all channels in the
network, order them chronologically by channel, and create blocks
of transactions per channel.
[0060] The blocks of the transaction are delivered from the
ordering node 284 to all peer nodes 281-283 on the channel. The
transactions 294 within the block are validated to ensure any
endorsement policy is fulfilled and to ensure that there have been
no changes to ledger state for read set variables since the read
set was generated by the transaction execution. Transactions in the
block are tagged as being valid or invalid. Furthermore, in step
295 each peer node 281-283 appends the block to the channel's
chain, and for each valid transaction the write sets are committed
to current state database. An event is emitted, to notify the
client application that the transaction (invocation) has been
immutably appended to the chain, as well as to notify whether the
transaction was validated or invalidated.
[0061] FIG. 3A illustrates an example of a permissioned blockchain
network 300, which features a distributed, decentralized
peer-to-peer architecture. In this example, a blockchain user 302
may initiate a transaction to the permissioned blockchain 304. In
this example, the transaction can be a deploy, invoke, or query,
and may be issued through a client-side application leveraging an
SDK, directly through an API, etc. Networks may provide access to a
regulator 306, such as an auditor. A blockchain network operator
308 manages member permissions, such as enrolling the regulator 306
as an "auditor" and the blockchain user 302 as a "client". An
auditor could be restricted only to querying the ledger whereas a
client could be authorized to deploy, invoke, and query certain
types of chaincode.
[0062] A blockchain developer 310 can write chaincode and
client-side applications. The blockchain developer 310 can deploy
chaincode directly to the network through an interface. To include
credentials from a traditional data source 312 in chaincode, the
developer 310 could use an out-of-band connection to access the
data. In this example, the blockchain user 302 connects to the
permissioned blockchain 304 through a peer node 314. Before
proceeding with any transactions, the peer node 314 retrieves the
user's enrollment and transaction certificates from a certificate
authority 316, which manages user roles and permissions. In some
cases, blockchain users must possess these digital certificates in
order to transact on the permissioned blockchain 304. Meanwhile, a
user attempting to utilize chaincode may be required to verify
their credentials on the traditional data source 312. To confirm
the user's authorization, chaincode can use an out-of-band
connection to this data through a traditional processing platform
318.
[0063] FIG. 3B illustrates another example of a permissioned
blockchain network 320, which features a distributed, decentralized
peer-to-peer architecture. In this example, a blockchain user 322
may submit a transaction to the permissioned blockchain 324. In
this example, the transaction can be a deploy, invoke, or query,
and may be issued through a client-side application leveraging an
SDK, directly through an API, etc. Networks may provide access to a
regulator 326, such as an auditor. A blockchain network operator
328 manages member permissions, such as enrolling the regulator 326
as an "auditor" and the blockchain user 322 as a "client". An
auditor could be restricted only to querying the ledger whereas a
client could be authorized to deploy, invoke, and query certain
types of chaincode.
[0064] A blockchain developer 330 writes chaincode and client-side
applications. The blockchain developer 330 can deploy chaincode
directly to the network through an interface. To include
credentials from a traditional data source 332 in chaincode, the
developer 330 could use an out-of-band connection to access the
data. In this example, the blockchain user 322 connects to the
network through a peer node 334. Before proceeding with any
transactions, the peer node 334 retrieves the user's enrollment and
transaction certificates from the certificate authority 336. In
some cases, blockchain users must possess these digital
certificates in order to transact on the permissioned blockchain
324. Meanwhile, a user attempting to utilize chaincode may be
required to verify their credentials on the traditional data source
332. To confirm the user's authorization, chaincode can use an
out-of-band connection to this data through a traditional
processing platform 338.
[0065] In some embodiments, the blockchain herein may be a
permissionless blockchain. In contrast with permissioned
blockchains which require permission to join, anyone can join a
permissionless blockchain. For example, to join a permissionless
blockchain a user may create a personal address and begin
interacting with the network, by submitting transactions, and hence
adding entries to the ledger. Additionally, all parties have the
choice of running a node on the system and employing the mining
protocols to help verify transactions.
[0066] FIG. 3C illustrates a process 350 of a transaction being
processed by a permissionless blockchain 352 including a plurality
of nodes 354. A sender 356 desires to send payment or some other
form of value (e.g., a deed, medical records, a contract, a good, a
service, or any other asset that can be encapsulated in a digital
record) to a recipient 358 via the permissionless blockchain 352.
In one embodiment, each of the sender device 356 and the recipient
device 358 may have digital wallets (associated with the blockchain
352) that provide user interface controls and a display of
transaction parameters. In response, the transaction is broadcast
throughout the blockchain 352 to the nodes 354. Depending on the
blockchain's 352 network parameters the nodes verify 360 the
transaction based on rules (which may be pre-defined or dynamically
allocated) established by the permissionless blockchain 352
creators. For example, this may include verifying identities of the
parties involved, etc. The transaction may be verified immediately
or it may be placed in a queue with other transactions and the
nodes 354 determine if the transactions are valid based on a set of
network rules.
[0067] In structure 362, valid transactions are formed into a block
and sealed with a lock (hash). This process may be performed by
mining nodes among the nodes 354. Mining nodes may utilize
additional software specifically for mining and creating blocks for
the permissionless blockchain 352. Each block may be identified by
a hash (e.g., 256 bit number, etc.) created using an algorithm
agreed upon by the network. Each block may include a header, a
pointer or reference to a hash of a previous block's header in the
chain, and a group of valid transactions. The reference to the
previous block's hash is associated with the creation of the secure
independent chain of blocks.
[0068] Before blocks can be added to the blockchain, the blocks
must be validated. Validation for the permissionless blockchain 352
may include a proof-of-work (PoW) which is a solution to a puzzle
derived from the block's header. Although not shown in the example
of FIG. 3C, another process for validating a block is
proof-of-stake. Unlike the proof-of-work, where the algorithm
rewards miners who solve mathematical problems, with the proof of
stake, a creator of a new block is chosen in a deterministic way,
depending on its wealth, also defined as "stake." Then, a similar
proof is performed by the selected/chosen node.
[0069] With mining 364, nodes try to solve the block by making
incremental changes to one variable until the solution satisfies a
network-wide target. This creates the PoW thereby ensuring correct
answers. In other words, a potential solution must prove that
computing resources were drained in solving the problem. In some
types of permissionless blockchains, miners may be rewarded with
value (e.g., coins, etc.) for correctly mining a block.
[0070] Here, the PoW process, alongside the chaining of blocks,
makes modifications of the blockchain extremely difficult, as an
attacker must modify all subsequent blocks in order for the
modifications of one block to be accepted. Furthermore, as new
blocks are mined, the difficulty of modifying a block increases,
and the number of subsequent blocks increases. With distribution
366, the successfully validated block is distributed through the
permissionless blockchain 352 and all nodes 354 add the block to a
majority chain which is the permissionless blockchain's 352
auditable ledger. Furthermore, the value in the transaction
submitted by the sender 356 is deposited or otherwise transferred
to the digital wallet of the recipient device 358.
[0071] FIG. 4A illustrates an architecture of peer node 400 with a
trace collection module 406 running therein according to example
embodiments. Referring to FIG. 4A, a privileged (protected) trace
collection module 406 may be implemented and executed by each peer
to collect traces of system calls from chaincode 402 and 403 to
operating system as evidence of correct execution during a period
of time. Here, the peer node 400 may include peer node software 401
for integrating with a blockchain network, and a chaincode (e.g.,
chaincode 402, 403, etc.) which may be invoked to access ledger
data and perform any necessary business logic of the peer node 400.
The peer node software 401 and the chaincodes 402 and 403 may
execute within a runtime 404 of the peer node 400. The chaincode
402 and 403 may request service (system calls) from the operating
system kernel 405 of the operating system on which the chaincode
402 and 403 is executing on. A hardware layer 407 may include the
physical components necessary for running the peer node software
401, the chaincodes 402 and 403, the operating system 405, and the
trace collection module 406.
[0072] According to various embodiments, the trace collection
module 406 may collect system calls made by the chaincode 402 and
403 with respect to the operating system 405. The trace collection
module 406 may be a small module on the peer node 400 that has
hypervisor privilege which protects runtime integrity' captures
chaincode information from the operating system 405, and collects
system call traces at runtime from the chaincode 402 and 403 during
a period of analysis. Although not shown in FIG. 4A, the hardware
407 may include a trusted platform module within the hardware 407
to make sure that correct version of the operating system and the
trace collection module 406 is running on the peer node 400.
[0073] The trace collection module 406 may bind with a subsystem
running on the peer node. With the use of this binding, the trace
collection module 406 may collect all system calls made by the
business logic of the chaincodes 402 and 403. The collected calls
can include any system call made by the chaincode container. Some
non-limiting examples of system calls include access, alarm, bind,
brk, close, connect, create, epoll, fdatasync, fork, listen, poll,
read, and the like as well as get commands, set commands, etc.
[0074] The trace collection module 406 on each peer may
independently collect call traces and then submit an encrypted copy
of the traces periodically after some time (called as a round) to a
misbehavior detection chaincode 412 executing on an arbitrator node
410. In each round, the trace collection module 406 may generate a
random round key for encryption of the traces. The collected system
calls are collected and encrypted. Furthermore, the trace
collection module 406 may transmit the encrypted system calls along
with the random round key to the misbehavior detecting chaincode
412 (to decrypt the encrypted traces). This two-step process may be
performed so that a misbehaving peer cannot look at the traces
submitted by other peers and submit them as their own, which
prevents against Sybil attacks.
[0075] The misbehavior detection chaincode 412 looks at each trace
and creates a map containing information about number of times
(frequency) each unique system call was executed by a particular
peer. An example of the misbehavior detection chaincode 412
creating a system call map 430 is shown in FIG. 4B. Here, four
peers A, B, C, and D are part of a common endorsement process and
share chaincode for implementing such endorsement process. Here,
trace collection modules on each of the four peers send system call
traces 421, 422, 423, and 424, corresponding to system calls
collected from peers A, B, C, and D, during a predetermined period
of time including the endorsement process.
[0076] According to various embodiments, the misbehavior detection
chaincode 412 may analyze the system calls within the traces 421,
422, 423, and 424, and identify which system calls are shared by a
predetermined amount of the peer nodes. For example, the
misbehavior detection chaincode 412 may identify any system calls
that are performed by a majority of the peer nodes as being a
required system call necessary to perform the endorsement process
through the chaincode. The misbehavior detecting chaincode 412 may
build the system call map 430 which includes only a set of system
calls that are associated with the endorsement process implemented
through the shared chaincode among the peers A-D. Once the
misbehavior detecting chaincode 412 has created the system call map
430, the misbehavior detecting chaincode can use the system call
map 430 to identify any misbehaving nodes that are not performing
the set of system calls.
[0077] For example, as a pre-step, the arbitrator 410 (misbehavior
detecting chaincode 412) may identify the endorser nodes (peers
A-D) from the blockchain ledger, and receive the system calls from
only those nodes. The misbehavior detecting chaincode 412 may, for
each separate set of transactions (which were executed by some set
of same peers), build a frequency map (i.e. how many times each
system call was executed by each peer for all the peers which
executed that particular set of transactions. The misbehavior
detecting chaincode 412 may create a majority set containing the
calls made by at least a majority (or other predetermined amount)
of the peers A-D which executed the transaction in each frequency
map. The majority set may be referred to as the system call map
430.
[0078] Referring to FIG. 4C, the misbehavior detecting chaincode
412 may perform a process 450 to detect whether any of the peers
failed to fully contribute to the endorsement process. For example,
if the system call map 430 includes a proper subset of the set of
calls made by the peer, then the peer must have executed the
transaction and hence is honest, else it is lying. In this example,
peers A, B, and C each include the system calls within the system
call map 430. Therefore, these peers are acting honestly and fully
contributing. However, peer D is determined to be acting
dishonestly (free-riding) because the system calls 424 of peer D
are missing system calls 432 from the system call map 430. In
response, the arbitrator 410 can generate a warning or an alarm,
and send the alarm to a user interface 440 of an admin device, a
client, a peer node, etc. Also, a notification of the misbehaving
peer can be stored in a blockchain, an off-chain storage, or the
like.
[0079] FIG. 5 illustrates a method 500 of identifying a free-riding
node within a blockchain network according to example embodiments.
Referring to FIG. 5, in 510 the method may include receiving system
calls captured from a plurality of peer nodes of a blockchain that
occurred within a predetermined period of time. For example, the
system calls may be independently captured by the plurality of peer
nodes based on a trace of chaincode that commonly runs on the
plurality of peer nodes. The system calls may be independently
detected by respective trace modules on the peer nodes and
forwarded to an aggregator system such as an arbitrator.
[0080] In 520, the method may include determining a subset of
system calls among the received system calls that correspond to a
blockchain process performed during the predetermined period of
time. For example, the determining may include determining a subset
of system calls that were performed by more than a predetermined
number (e.g., a majority, etc.) of the peer nodes within the
predetermined period of time. In some embodiments, the determining
may include generating a map which identifies how many peer nodes
performed each system call among the system calls, and identifying
the subset of system calls based on the map. In some embodiments,
the identifying may include identifying system calls that were
performed by a majority of the peer nodes, as the subset of system
calls.
[0081] In 530, the method may include detecting a free-riding peer
node from among the plurality of peer nodes based on the identified
subset of system calls with respect to system calls of the
free-riding peer node within the predetermined period of time, and,
in 540, the method may include storing an indicator of the
free-riding peer node. Here, the system may compare the map of
system calls of the free-riding node to the map generated from all
nodes, and identify one or more missing calls. In some embodiments,
the method may further include generating and displaying an alarm
via a user interface, in response to detecting the free-riding peer
node. In some embodiments, the detecting may include detecting the
existence of the free riding peer node in response to detecting a
failure by the free-riding peer node to perform a system call from
among the identified subset of system calls. In some embodiments,
the detecting the free-riding peer node is performed via
misbehavior identification chaincode.
[0082] FIG. 6A illustrates an example system 600 that includes a
physical infrastructure 610 configured to perform various
operations according to example embodiments. Referring to FIG. 6A,
the physical infrastructure 610 includes a module 612 and a module
614. The module 614 includes a blockchain 620 and a smart contract
630 (which may reside on the blockchain 620), that may execute any
of the operational steps 608 (in module 612) included in any of the
example embodiments. The steps/operations 608 may include one or
more of the embodiments described or depicted and may represent
output or written information that is written or read from one or
more smart contracts 630 and/or blockchains 620. The physical
infrastructure 610, the module 612, and the module 614 may include
one or more computers, servers, processors, memories, and/or
wireless communication devices. Further, the module 612 and the
module 614 may be a same module.
[0083] FIG. 6B illustrates another example system 640 configured to
perform various operations according to example embodiments.
Referring to FIG. 6B, the system 640 includes a module 612 and a
module 614. The module 614 includes a blockchain 620 and a smart
contract 630 (which may reside on the blockchain 620), that may
execute any of the operational steps 608 (in module 612) included
in any of the example embodiments. The steps/operations 608 may
include one or more of the embodiments described or depicted and
may represent output or written information that is written or read
from one or more smart contracts 630 and/or blockchains 620. The
physical infrastructure 610, the module 612, and the module 614 may
include one or more computers, servers, processors, memories,
and/or wireless communication devices. Further, the module 612 and
the module 614 may be a same module.
[0084] FIG. 6C illustrates an example system configured to utilize
a smart contract configuration among contracting parties and a
mediating server configured to enforce the smart contract terms on
the blockchain according to example embodiments. Referring to FIG.
6C, the configuration 650 may represent a communication session, an
asset transfer session or a process or procedure that is driven by
a smart contract 630 which explicitly identifies one or more user
devices 652 and/or 656. The execution, operations and results of
the smart contract execution may be managed by a server 654.
Content of the smart contract 630 may require digital signatures by
one or more of the entities 652 and 656 which are parties to the
smart contract transaction. The results of the smart contract
execution may be written to a blockchain 620 as a blockchain
transaction. The smart contract 630 resides on the blockchain 620
which may reside on one or more computers, servers, processors,
memories, and/or wireless communication devices.
[0085] FIG. 6D illustrates a system 660 including a blockchain,
according to example embodiments. Referring to the example of FIG.
6D, an application programming interface (API) gateway 662 provides
a common interface for accessing blockchain logic (e.g., smart
contract 630 or other chaincode) and data (e.g., distributed
ledger, etc.). In this example, the API gateway 662 is a common
interface for performing transactions (invoke, queries, etc.) on
the blockchain by connecting one or more entities 652 and 656 to a
blockchain peer (i.e., server 654). Here, the server 654 is a
blockchain network peer component that holds a copy of the world
state and a distributed ledger allowing clients 652 and 656 to
query data on the world state as well as submit transactions into
the blockchain network where, depending on the smart contract 630
and endorsement policy, endorsing peers will run the smart
contracts 630.
[0086] The above embodiments may be implemented in hardware, in a
computer program executed by a processor, in firmware, or in a
combination of the above. A computer program may be embodied on a
computer readable medium, such as a storage medium. For example, a
computer program may reside in random access memory ("RAM"), flash
memory, read-only memory ("ROM"), erasable programmable read-only
memory ("EPROM"), electrically erasable programmable read-only
memory ("EEPROM"), registers, hard disk, a removable disk, a
compact disk read-only memory ("CD-ROM"), or any other form of
storage medium known in the art.
[0087] An exemplary storage medium may be coupled to the processor
such that the processor may read information from, and write
information to, the storage medium. In the alternative, the storage
medium may be integral to the processor. The processor and the
storage medium may reside in an application specific integrated
circuit ("ASIC"). In the alternative, the processor and the storage
medium may reside as discrete components.
[0088] FIG. 7A illustrates a process 700 of a new block being added
to a distributed ledger 720, according to example embodiments, and
FIG. 7B illustrates contents of a new data block structure 730 for
blockchain, according to example embodiments. Referring to FIG. 7A,
clients (not shown) may submit transactions to blockchain nodes
711, 712, and/or 713. Clients may be instructions received from any
source to enact activity on the blockchain 720. As an example,
clients may be applications that act on behalf of a requester, such
as a device, person or entity to propose transactions for the
blockchain. The plurality of blockchain peers (e.g., blockchain
nodes 711, 712, and 713) may maintain a state of the blockchain
network and a copy of the distributed ledger 720. Different types
of blockchain nodes/peers may be present in the blockchain network
including endorsing peers which simulate and endorse transactions
proposed by clients and committing peers which verify endorsements,
validate transactions, and commit transactions to the distributed
ledger 720. In this example, the blockchain nodes 711, 712, and 713
may perform the role of endorser node, committer node, or both.
[0089] The distributed ledger 720 includes a blockchain which
stores immutable, sequenced records in blocks, and a state database
724 (current world state) maintaining a current state of the
blockchain 722. One distributed ledger 720 may exist per channel
and each peer maintains its own copy of the distributed ledger 720
for each channel of which they are a member. The blockchain 722 is
a transaction log, structured as hash-linked blocks where each
block contains a sequence of N transactions. Blocks may include
various components such as shown in FIG. 7B. The linking of the
blocks (shown by arrows in FIG. 7A) may be generated by adding a
hash of a prior block's header within a block header of a current
block. In this way, all transactions on the blockchain 722 are
sequenced and cryptographically linked together preventing
tampering with blockchain data without breaking the hash links.
Furthermore, because of the links, the latest block in the
blockchain 722 represents every transaction that has come before
it. The blockchain 722 may be stored on a peer file system (local
or attached storage), which supports an append-only blockchain
workload.
[0090] The current state of the blockchain 722 and the distributed
ledger 722 may be stored in the state database 724. Here, the
current state data represents the latest values for all keys ever
included in the chain transaction log of the blockchain 722.
Chaincode invocations execute transactions against the current
state in the state database 724. To make these chaincode
interactions extremely efficient, the latest values of all keys are
stored in the state database 724. The state database 724 may
include an indexed view into the transaction log of the blockchain
722, it can therefore be regenerated from the chain at any time.
The state database 724 may automatically get recovered (or
generated if needed) upon peer startup, before transactions are
accepted.
[0091] Endorsing nodes receive transactions from clients and
endorse the transaction based on simulated results. Endorsing nodes
hold smart contracts which simulate the transaction proposals. When
an endorsing node endorses a transaction, the endorsing nodes
creates a transaction endorsement which is a signed response from
the endorsing node to the client application indicating the
endorsement of the simulated transaction. The method of endorsing a
transaction depends on an endorsement policy which may be specified
within chaincode. An example of an endorsement policy is "the
majority of endorsing peers must endorse the transaction".
Different channels may have different endorsement policies.
Endorsed transactions are forward by the client application to
ordering service 710.
[0092] The ordering service 710 accepts endorsed transactions,
orders them into a block, and delivers the blocks to the committing
peers. For example, the ordering service 710 may initiate a new
block when a threshold of transactions has been reached, a timer
times out, or another condition. In the example of FIG. 7A,
blockchain node 712 is a committing peer that has received a new
data new data block 730 for storage on blockchain 720. The first
block in the blockchain may be referred to as a genesis block which
includes information about the blockchain, its members, the data
stored therein, etc.
[0093] The ordering service 710 may be made up of a cluster of
orderers. The ordering service 710 does not process transactions,
smart contracts, or maintain the shared ledger. Rather, the
ordering service 710 may accept the endorsed transactions and
specifies the order in which those transactions are committed to
the distributed ledger 720. The architecture of the blockchain
network may be designed such that the specific implementation of
`ordering` (e.g., Solo, Kafka, BFT, etc.) becomes a pluggable
component.
[0094] Transactions are written to the distributed ledger 720 in a
consistent order. The order of transactions is established to
ensure that the updates to the state database 724 are valid when
they are committed to the network. Unlike a cryptocurrency
blockchain system (e.g., Bitcoin, etc.) where ordering occurs
through the solving of a cryptographic puzzle, or mining, in this
example the parties of the distributed ledger 720 may choose the
ordering mechanism that best suits that network.
[0095] When the ordering service 710 initializes a new data block
730, the new data block 730 may be broadcast to committing peers
(e.g., blockchain nodes 711, 712, and 713). In response, each
committing peer validates the transaction within the new data block
730 by checking to make sure that the read set and the write set
still match the current world state in the state database 724.
Specifically, the committing peer can determine whether the read
data that existed when the endorsers simulated the transaction is
identical to the current world state in the state database 724.
When the committing peer validates the transaction, the transaction
is written to the blockchain 722 on the distributed ledger 720, and
the state database 724 is updated with the write data from the
read-write set. If a transaction fails, that is, if the committing
peer finds that the read-write set does not match the current world
state in the state database 724, the transaction ordered into a
block will still be included in that block, but it will be marked
as invalid, and the state database 724 will not be updated.
[0096] Referring to FIG. 7B, a new data block 730 (also referred to
as a data block) that is stored on the blockchain 722 of the
distributed ledger 720 may include multiple data segments such as a
block header 740, block data 750, and block metadata 760. It should
be appreciated that the various depicted blocks and their contents,
such as new data block 730 and its contents. shown in FIG. 7B are
merely examples and are not meant to limit the scope of the example
embodiments. The new data block 730 may store transactional
information of N transaction(s) (e.g., 1, 10, 100, 500, 1000, 2000,
3000, etc.) within the block data 750. The new data block 730 may
also include a link to a previous block (e.g., on the blockchain
722 in FIG. 7A) within the block header 740. In particular, the
block header 740 may include a hash of a previous block's header.
The block header 740 may also include a unique block number, a hash
of the block data 750 of the new data block 730, and the like. The
block number of the new data block 730 may be unique and assigned
in various orders, such as an incremental/sequential order starting
from zero.
[0097] The block data 750 may store transactional information of
each transaction that is recorded within the new data block 730.
For example, the transaction data may include one or more of a type
of the transaction, a version, a timestamp, a channel ID of the
distributed ledger 720, a transaction ID, an epoch, a payload
visibility, a chaincode path (deploy tx), a chaincode name, a
chaincode version, input (chaincode and functions), a client
(creator) identify such as a public key and certificate, a
signature of the client, identities of endorsers, endorser
signatures, a proposal hash, chaincode events, response status,
namespace, a read set (list of key and version read by the
transaction, etc.), a write set (list of key and value, etc.), a
start key, an end key, a list of keys, a Merkel tree query summary,
and the like. The transaction data may be stored for each of the N
transactions.
[0098] The block metadata 760 may store multiple fields of metadata
(e.g., as a byte array, etc.). Metadata fields may include
signature on block creation, a reference to a last configuration
block, a transaction filter identifying valid and invalid
transactions within the block, last offset persisted of an ordering
service that ordered the block, and the like. The signature, the
last configuration block, and the orderer metadata may be added by
the ordering service 710. Meanwhile, a committer of the block (such
as blockchain node 712) may add validity/invalidity information
based on an endorsement policy, verification of read/write sets,
and the like. The transaction filter may include a byte array of a
size equal to the number of transactions in the block data 750 and
a validation code identifying whether a transaction was
valid/invalid.
[0099] FIG. 7C illustrates an embodiment of a blockchain 770 for
digital content in accordance with the embodiments described
herein. The digital content may include one or more files and
associated information. The files may include media, images, video,
audio, text, links, graphics, animations, web pages, documents, or
other forms of digital content. The immutable, append-only aspects
of the blockchain serve as a safeguard to protect the integrity,
validity, and authenticity of the digital content, making it
suitable use in legal proceedings where admissibility rules apply
or other settings where evidence is taken in to consideration or
where the presentation and use of digital information is otherwise
of interest. In this case, the digital content may be referred to
as digital evidence.
[0100] The blockchain may be formed in various ways. In one
embodiment, the digital content may be included in and accessed
from the blockchain itself. For example, each block of the
blockchain may store a hash value of reference information (e.g.,
header, value, etc.) along the associated digital content. The hash
value and associated digital content may then be encrypted
together. Thus, the digital content of each block may be accessed
by decrypting each block in the blockchain, and the hash value of
each block may be used as a basis to reference a previous block.
This may be illustrated as follows:
TABLE-US-00001 Block 1 Block 2 . . . Block N Hash Value 1 Hash
Value 2 Hash Value N Digital Content 1 Digital Content 2 Digital
Content N
[0101] In one embodiment, the digital content may be not included
in the blockchain. For example, the blockchain may store the
encrypted hashes of the content of each block without any of the
digital content. The digital content may be stored in another
storage area or memory address in association with the hash value
of the original file. The other storage area may be the same
storage device used to store the blockchain or may be a different
storage area or even a separate relational database. The digital
content of each block may be referenced or accessed by obtaining or
querying the hash value of a block of interest and then looking up
that has value in the storage area, which is stored in
correspondence with the actual digital content. This operation may
be performed, for example, a database gatekeeper. This may be
illustrated as follows:
TABLE-US-00002 Blockchain Storage Area Block 1 Hash Value Block 1
Hash Value . . . Content . . . . . . Block N Hash Value Block N
Hash Value . . . Content
[0102] In the example embodiment of FIG. 7C, the blockchain 770
includes a number of blocks 778.sub.1, 778.sub.2, . . . 778.sub.N
cryptographically linked in an ordered sequence, where N.gtoreq.1.
The encryption used to link the blocks 778.sub.1, 778.sub.2, . . .
778.sub.N may be any of a number of keyed or un-keyed Hash
functions. In one embodiment, the blocks 778.sub.1, 778.sub.2, . .
. 778.sub.N are subject to a hash function which produces n-bit
alphanumeric outputs (where n is 256 or another number) from inputs
that are based on information in the blocks. Examples of such a
hash function include, but are not limited to, a SHA-type (SHA
stands for Secured Hash Algorithm) algorithm, Merkle-Damgard
algorithm, HAIFA algorithm, Merkle-tree algorithm, nonce-based
algorithm, and a non-collision-resistant PRF algorithm. In another
embodiment, the blocks 778.sub.1, 778.sub.2, . . . , 778.sub.N may
be cryptographically linked by a function that is different from a
hash function. For purposes of illustration, the following
description is made with reference to a hash function, e.g.,
SHA-2.
[0103] Each of the blocks 778.sub.1, 778.sub.2, . . . , 778.sub.N
in the blockchain includes a header, a version of the file, and a
value. The header and the value are different for each block as a
result of hashing in the blockchain. In one embodiment, the value
may be included in the header. As described in greater detail
below, the version of the file may be the original file or a
different version of the original file.
[0104] The first block 778.sub.1 in the blockchain is referred to
as the genesis block and includes the header 772.sub.1, original
file 774.sub.1, and an initial value 776.sub.1. The hashing scheme
used for the genesis block, and indeed in all subsequent blocks,
may vary. For example, all the information in the first block
778.sub.1 may be hashed together and at one time, or each or a
portion of the information in the first block 778.sub.1 may be
separately hashed and then a hash of the separately hashed portions
may be performed.
[0105] The header 772.sub.1 may include one or more initial
parameters, which, for example, may include a version number,
timestamp, nonce, root information, difficulty level, consensus
protocol, duration, media format, source, descriptive keywords,
and/or other information associated with original file 774.sub.1
and/or the blockchain. The header 772.sub.1 may be generated
automatically (e.g., by blockchain network managing software) or
manually by a blockchain participant. Unlike the header in other
blocks 778.sub.2 to 778.sub.N in the blockchain, the header
772.sub.1 in the genesis block does not reference a previous block,
simply because there is no previous block.
[0106] The original file 774.sub.1 in the genesis block may be, for
example, data as captured by a device with or without processing
prior to its inclusion in the blockchain. The original file
774.sub.1 is received through the interface of the system from the
device, media source, or node. The original file 774.sub.1 is
associated with metadata, which, for example, may be generated by a
user, the device, and/or the system processor, either manually or
automatically. The metadata may be included in the first block
778.sub.1 in association with the original file 774.sub.1.
[0107] The value 776.sub.1 in the genesis block is an initial value
generated based on one or more unique attributes of the original
file 774.sub.1. In one embodiment, the one or more unique
attributes may include the hash value for the original file
774.sub.1, metadata for the original file 774.sub.1, and other
information associated with the file. In one implementation, the
initial value 776.sub.1 may be based on the following unique
attributes: [0108] 1) SHA-2 computed hash value for the original
file [0109] 2) originating device ID [0110] 3) starting timestamp
for the original file [0111] 4) initial storage location of the
original file [0112] 5) blockchain network member ID for software
to currently control the original file and associated metadata
[0113] The other blocks 778.sub.2 to 778.sub.N in the blockchain
also have headers, files, and values. However, unlike the first
block 772.sub.1, each of the headers 772.sub.2 to 772.sub.N in the
other blocks includes the hash value of an immediately preceding
block. The hash value of the immediately preceding block may be
just the hash of the header of the previous block or may be the
hash value of the entire previous block. By including the hash
value of a preceding block in each of the remaining blocks, a trace
can be performed from the Nth block back to the genesis block (and
the associated original file) on a block-by-block basis, as
indicated by arrows 780, to establish an auditable and immutable
chain-of-custody.
[0114] Each of the header 772.sub.2 to 772.sub.N in the other
blocks may also include other information, e.g., version number,
timestamp, nonce, root information, difficulty level, consensus
protocol, and/or other parameters or information associated with
the corresponding files and/or the blockchain in general.
[0115] The files 774.sub.2 to 774.sub.N in the other blocks may be
equal to the original file or may be a modified version of the
original file in the genesis block depending, for example, on the
type of processing performed. The type of processing performed may
vary from block to block. The processing may involve, for example,
any modification of a file in a preceding block, such as redacting
information or otherwise changing the content of, taking
information away from, or adding or appending information to the
files.
[0116] Additionally, or alternatively, the processing may involve
merely copying the file from a preceding block, changing a storage
location of the file, analyzing the file from one or more preceding
blocks, moving the file from one storage or memory location to
another, or performing action relative to the file of the
blockchain and/or its associated metadata. Processing which
involves analyzing a file may include, for example, appending,
including, or otherwise associating various analytics, statistics,
or other information associated with the file.
[0117] The values in each of the other blocks 776.sub.2 to
776.sub.N in the other blocks are unique values and are all
different as a result of the processing performed. For example, the
value in any one block corresponds to an updated version of the
value in the previous block. The update is reflected in the hash of
the block to which the value is assigned. The values of the blocks
therefore provide an indication of what processing was performed in
the blocks and also permit a tracing through the blockchain back to
the original file. This tracking confirms the chain-of-custody of
the file throughout the entire blockchain.
[0118] For example, consider the case where portions of the file in
a previous block are redacted, blocked out, or pixelated in order
to protect the identity of a person shown in the file. In this
case, the block including the redacted file will include metadata
associated with the redacted file, e.g., how the redaction was
performed, who performed the redaction, timestamps where the
redaction(s) occurred, etc. The metadata may be hashed to form the
value. Because the metadata for the block is different from the
information that was hashed to form the value in the previous
block, the values are different from one another and may be
recovered when decrypted.
[0119] In one embodiment, the value of a previous block may be
updated (e.g., a new hash value computed) to form the value of a
current block when any one or more of the following occurs. The new
hash value may be computed by hashing all or a portion of the
information noted below, in this example embodiment. [0120] a) new
SHA-2 computed hash value if the file has been processed in any way
(e.g., if the file was redacted, copied, altered, accessed, or some
other action was taken) [0121] b) new storage location for the file
[0122] c) new metadata identified associated with the file [0123]
d) transfer of access or control of the file from one blockchain
participant to another blockchain participant
[0124] FIG. 7D illustrates an embodiment of a block which may
represent the structure of the blocks in the blockchain 790 in
accordance with one embodiment. The block, Block.sub.i, includes a
header 772.sub.1, a file 774.sub.1, and a value 776.sub.1.
[0125] The header 772.sub.1 includes a hash value of a previous
block Block.sub.i-1 and additional reference information, which,
for example, may be any of the types of information (e.g., header
information including references, characteristics, parameters,
etc.) discussed herein. All blocks reference the hash of a previous
block except, of course, the genesis block. The hash value of the
previous block may be just a hash of the header in the previous
block or a hash of all or a portion of the information in the
previous block, including the file and metadata.
[0126] The file 774.sub.i includes a plurality of data, such as
Data 1, Data 2, . . . , Data N in sequence. The data are tagged
with metadata Metadata 1, Metadata 2, . . . , Metadata N which
describe the content and/or characteristics associated with the
data. For example, the metadata for each data may include
information to indicate a timestamp for the data, process the data,
keywords indicating the persons or other content depicted in the
data, and/or other features that may be helpful to establish the
validity and content of the file as a whole, and particularly its
use a digital evidence, for example, as described in connection
with an embodiment discussed below. In addition to the metadata,
each data may be tagged with reference REF.sub.1, REF.sub.2, . . .
, REF.sub.N to a previous data to prevent tampering, gaps in the
file, and sequential reference through the file.
[0127] Once the metadata is assigned to the data (e.g., through a
smart contract), the metadata cannot be altered without the hash
changing, which can easily be identified for invalidation. The
metadata, thus, creates a data log of information that may be
accessed for use by participants in the blockchain.
[0128] The value 776.sub.i is a hash value or other value computed
based on any of the types of information previously discussed. For
example, for any given block Block.sub.i, the value for that block
may be updated to reflect the processing that was performed for
that block, e.g., new hash value, new storage location, new
metadata for the associated file, transfer of control or access,
identifier, or other action or information to be added. Although
the value in each block is shown to be separate from the metadata
for the data of the file and header, the value may be based, in
part or whole, on this metadata in another embodiment.
[0129] Once the blockchain 770 is formed, at any point in time, the
immutable chain-of-custody for the file may be obtained by querying
the blockchain for the transaction history of the values across the
blocks. This query, or tracking procedure, may begin with
decrypting the value of the block that is most currently included
(e.g., the last (N.sup.th) block), and then continuing to decrypt
the value of the other blocks until the genesis block is reached
and the original file is recovered. The decryption may involve
decrypting the headers and files and associated metadata at each
block, as well.
[0130] Decryption is performed based on the type of encryption that
took place in each block. This may involve the use of private keys,
public keys, or a public key-private key pair. For example, when
asymmetric encryption is used, blockchain participants or a
processor in the network may generate a public key and private key
pair using a predetermined algorithm. The public key and private
key are associated with each other through some mathematical
relationship. The public key may be distributed publicly to serve
as an address to receive messages from other users, e.g., an IP
address or home address. The private key is kept secret and used to
digitally sign messages sent to other blockchain participants. The
signature is included in the message so that the recipient can
verify using the public key of the sender. This way, the recipient
can be sure that only the sender could have sent this message.
[0131] Generating a key pair may be analogous to creating an
account on the blockchain, but without having to actually register
anywhere. Also, every transaction that is executed on the
blockchain is digitally signed by the sender using their private
key. This signature ensures that only the owner of the account can
track and process (if within the scope of permission determined by
a smart contract) the file of the blockchain.
[0132] FIGS. 8A and 8B illustrate additional examples of use cases
for blockchain which may be incorporated and used herein. In
particular, FIG. 8A illustrates an example 800 of a blockchain 810
which stores machine learning (artificial intelligence) data.
Machine learning relies on vast quantities of historical data (or
training data) to build predictive models for accurate prediction
on new data. Machine learning software (e.g., neural networks,
etc.) can often sift through millions of records to unearth
non-intuitive patterns.
[0133] In the example of FIG. 8A, a host platform 820 builds and
deploys a machine learning model for predictive monitoring of
assets 830. Here, the host platform 820 may be a cloud platform, an
industrial server, a web server, a personal computer, a user
device, and the like. Assets 830 can be any type of asset (e.g.,
machine or equipment, etc.) such as an aircraft, locomotive,
turbine, medical machinery and equipment, oil and gas equipment,
boats, ships, vehicles, and the like. As another example, assets
830 may be non-tangible assets such as stocks, currency, digital
coins, insurance, or the like.
[0134] The blockchain 810 can be used to significantly improve both
a training process 802 of the machine learning model and a
predictive process 804 based on a trained machine learning model.
For example, in 802, rather than requiring a data
scientist/engineer or other user to collect the data, historical
data may be stored by the assets 830 themselves (or through an
intermediary, not shown) on the blockchain 810. This can
significantly reduce the collection time needed by the host
platform 820 when performing predictive model training. For
example, using smart contracts, data can be directly and reliably
transferred straight from its place of origin to the blockchain
810. By using the blockchain 810 to ensure the security and
ownership of the collected data, smart contracts may directly send
the data from the assets to the individuals that use the data for
building a machine learning model. This allows for sharing of data
among the assets 830.
[0135] The collected data may be stored in the blockchain 810 based
on a consensus mechanism. The consensus mechanism pulls in
(permissioned nodes) to ensure that the data being recorded is
verified and accurate. The data recorded is time-stamped,
cryptographically signed, and immutable. It is therefore auditable,
transparent, and secure. Adding IoT devices which write directly to
the blockchain can, in certain cases (i.e. supply chain,
healthcare, logistics, etc.), increase both the frequency and
accuracy of the data being recorded.
[0136] Furthermore, training of the machine learning model on the
collected data may take rounds of refinement and testing by the
host platform 820. Each round may be based on additional data or
data that was not previously considered to help expand the
knowledge of the machine learning model. In 802, the different
training and testing steps (and the data associated therewith) may
be stored on the blockchain 810 by the host platform 820. Each
refinement of the machine learning model (e.g., changes in
variables, weights, etc.) may be stored on the blockchain 810. This
provides verifiable proof of how the model was trained and what
data was used to train the model. Furthermore, when the host
platform 820 has achieved a finally trained model, the resulting
model may be stored on the blockchain 810.
[0137] After the model has been trained, it may be deployed to a
live environment where it can make predictions/decisions based on
the execution of the final trained machine learning model. For
example, in 804, the machine learning model may be used for
condition-based maintenance (CBM) for an asset such as an aircraft,
a wind turbine, a healthcare machine, and the like. In this
example, data fed back from the asset 830 may be input the machine
learning model and used to make event predictions such as failure
events, error codes, and the like. Determinations made by the
execution of the machine learning model at the host platform 820
may be stored on the blockchain 810 to provide auditable/verifiable
proof. As one non-limiting example, the machine learning model may
predict a future breakdown/failure to a part of the asset 830 and
create alert or a notification to replace the part. The data behind
this decision may be stored by the host platform 820 on the
blockchain 810. In one embodiment the features and/or the actions
described and/or depicted herein can occur on or with respect to
the blockchain 810.
[0138] New transactions for a blockchain can be gathered together
into a new block and added to an existing hash value. This is then
encrypted to create a new hash for the new block. This is added to
the next list of transactions when they are encrypted, and so on.
The result is a chain of blocks that each contain the hash values
of all preceding blocks. Computers that store these blocks
regularly compare their hash values to ensure that they are all in
agreement. Any computer that does not agree, discards the records
that are causing the problem. This approach is good for ensuring
tamper-resistance of the blockchain, but it is not perfect.
[0139] One way to game this system is for a dishonest user to
change the list of transactions in their favor, but in a way that
leaves the hash unchanged. This can be done by brute force, in
other words by changing a record, encrypting the result, and seeing
whether the hash value is the same. And if not, trying again and
again and again until it finds a hash that matches. The security of
blockchains is based on the belief that ordinary computers can only
perform this kind of brute force attack over time scales that are
entirely impractical, such as the age of the universe. By contrast,
quantum computers are much faster (1000s of times faster) and
consequently pose a much greater threat.
[0140] FIG. 8B illustrates an example 850 of a quantum-secure
blockchain 852 which implements quantum key distribution (QKD) to
protect against a quantum computing attack. In this example,
blockchain users can verify each other's identities using QKD. This
sends information using quantum particles such as photons, which
cannot be copied by an eavesdropper without destroying them. In
this way, a sender and a receiver through the blockchain can be
sure of each other's identity.
[0141] In the example of FIG. 8B, four users are present 854, 856,
858, and 860. Each of pair of users may share a secret key 862
(i.e., a QKD) between themselves. Since there are four nodes in
this example, six pairs of nodes exists, and therefore six
different secret keys 862 are used including QKD.sub.AB,
QKD.sub.AC, QKD.sub.AD, QKD.sub.BC, QKD.sub.BD, and QKD.sub.CD.
Each pair can create a QKD by sending information using quantum
particles such as photons, which cannot be copied by an
eavesdropper without destroying them. In this way, a pair of users
can be sure of each other's identity.
[0142] The operation of the blockchain 852 is based on two
procedures (i) creation of transactions, and (ii) construction of
blocks that aggregate the new transactions. New transactions may be
created similar to a traditional blockchain network. Each
transaction may contain information about a sender, a receiver, a
time of creation, an amount (or value) to be transferred, a list of
reference transactions that justifies the sender has funds for the
operation, and the like. This transaction record is then sent to
all other nodes where it is entered into a pool of unconfirmed
transactions. Here, two parties (i.e., a pair of users from among
854-860) authenticate the transaction by providing their shared
secret key 862 (QKD). This quantum signature can be attached to
every transaction making it exceedingly difficult to tamper with.
Each node checks their entries with respect to a local copy of the
blockchain 852 to verify that each transaction has sufficient
funds. However, the transactions are not yet confirmed.
[0143] Rather than perform a traditional mining process on the
blocks, the blocks may be created in a decentralized manner using a
broadcast protocol. At a predetermined period of time (e.g.,
seconds, minutes, hours, etc.) the network may apply the broadcast
protocol to any unconfirmed transaction thereby to achieve a
Byzantine agreement (consensus) regarding a correct version of the
transaction. For example, each node may possess a private value
(transaction data of that particular node). In a first round, nodes
transmit their private values to each other. In subsequent rounds,
nodes communicate the information they received in the previous
round from other nodes. Here, honest nodes are able to create a
complete set of transactions within a new block. This new block can
be added to the blockchain 852. In one embodiment the features
and/or the actions described and/or depicted herein can occur on or
with respect to the blockchain 852.
[0144] FIG. 9 illustrates an example system 900 that supports one
or more of the example embodiments described and/or depicted
herein. The system 900 comprises a computer system/server 902,
which is operational with numerous other general purpose or special
purpose computing system environments or configurations. Examples
of well-known computing systems, environments, and/or
configurations that may be suitable for use with computer
system/server 902 include, but are not limited to, personal
computer systems, server computer systems, thin clients, thick
clients, hand-held or laptop devices, multiprocessor systems,
microprocessor-based systems, set top boxes, programmable consumer
electronics, network PCs, minicomputer systems, mainframe computer
systems, and distributed cloud computing environments that include
any of the above systems or devices, and the like.
[0145] Computer system/server 902 may be described in the general
context of computer system-executable instructions, such as program
modules, being executed by a computer system. Generally, program
modules may include routines, programs, objects, components, logic,
data structures, and so on that perform particular tasks or
implement particular abstract data types. Computer system/server
902 may be practiced in distributed cloud computing environments
where tasks are performed by remote processing devices that are
linked through a communications network. In a distributed cloud
computing environment, program modules may be located in both local
and remote computer system storage media including memory storage
devices.
[0146] As shown in FIG. 9, computer system/server 902 in cloud
computing node 900 is shown in the form of a general-purpose
computing device. The components of computer system/server 902 may
include, but are not limited to, one or more processors or
processing units 904, a system memory 906, and a bus that couples
various system components including system memory 906 to processor
904.
[0147] The bus represents one or more of any of several types of
bus structures, including a memory bus or memory controller, a
peripheral bus, an accelerated graphics port, and a processor or
local bus using any of a variety of bus architectures. By way of
example, and not limitation, such architectures include Industry
Standard Architecture (ISA) bus, Micro Channel Architecture (MCA)
bus, Enhanced ISA (EISA) bus, Video Electronics Standards
Association (VESA) local bus, and Peripheral Component
Interconnects (PCI) bus.
[0148] Computer system/server 902 typically includes a variety of
computer system readable media. Such media may be any available
media that is accessible by computer system/server 902, and it
includes both volatile and non-volatile media, removable and
non-removable media. System memory 906, in one embodiment,
implements the flow diagrams of the other figures. The system
memory 906 can include computer system readable media in the form
of volatile memory, such as random-access memory (RAM) 910 and/or
cache memory 912. Computer system/server 902 may further include
other removable/non-removable, volatile/non-volatile computer
system storage media. By way of example only, storage system 914
can be provided for reading from and writing to a non-removable,
non-volatile magnetic media (not shown and typically called a "hard
drive"). Although not shown, a magnetic disk drive for reading from
and writing to a removable, non-volatile magnetic disk (e.g., a
"floppy disk"), and an optical disk drive for reading from or
writing to a removable, non-volatile optical disk such as a CD-ROM,
DVD-ROM or other optical media can be provided. In such instances,
each can be connected to the bus by one or more data media
interfaces. As will be further depicted and described below, memory
906 may include at least one program product having a set (e.g., at
least one) of program modules that are configured to carry out the
functions of various embodiments of the application.
[0149] Program/utility 916, having a set (at least one) of program
modules 918, may be stored in memory 906 by way of example, and not
limitation, as well as an operating system, one or more application
programs, other program modules, and program data. Each of the
operating system, one or more application programs, other program
modules, and program data or some combination thereof, may include
an implementation of a networking environment. Program modules 918
generally carry out the functions and/or methodologies of various
embodiments of the application as described herein.
[0150] As will be appreciated by one skilled in the art, aspects of
the present application may be embodied as a system, method, or
computer program product. Accordingly, aspects of the present
application may take the form of an entirely hardware embodiment,
an entirely software embodiment (including firmware, resident
software, micro-code, etc.) or an embodiment combining software and
hardware aspects that may all generally be referred to herein as a
"circuit," "module" or "system." Furthermore, aspects of the
present application may take the form of a computer program product
embodied in one or more computer readable medium(s) having computer
readable program code embodied thereon.
[0151] Computer system/server 902 may also communicate with one or
more external devices 920 such as a keyboard, a pointing device, a
display 922, etc.; one or more devices that enable a user to
interact with computer system/server 902; and/or any devices (e.g.,
network card, modem, etc.) that enable computer system/server 902
to communicate with one or more other computing devices. Such
communication can occur via I/O interfaces 924. Still yet, computer
system/server 902 can communicate with one or more networks such as
a local area network (LAN), a general wide area network (WAN),
and/or a public network (e.g., the Internet) via network adapter
926. As depicted, network adapter 926 communicates with the other
components of computer system/server 902 via a bus. It should be
understood that although not shown, other hardware and/or software
components could be used in conjunction with computer system/server
902. Examples, include, but are not limited to: microcode, device
drivers, redundant processing units, external disk drive arrays,
RAID systems, tape drives, and data archival storage systems,
etc.
[0152] Although an exemplary embodiment of at least one of a
system, method, and non-transitory computer readable medium has
been illustrated in the accompanied drawings and described in the
foregoing detailed description, it will be understood that the
application is not limited to the embodiments disclosed, but is
capable of numerous rearrangements, modifications, and
substitutions as set forth and defined by the following claims. For
example, the capabilities of the system of the various figures can
be performed by one or more of the modules or components described
herein or in a distributed architecture and may include a
transmitter, receiver or pair of both. For example, all or part of
the functionality performed by the individual modules, may be
performed by one or more of these modules. Further, the
functionality described herein may be performed at various times
and in relation to various events, internal or external to the
modules or components. Also, the information sent between various
modules can be sent between the modules via at least one of: a data
network, the Internet, a voice network, an Internet Protocol
network, a wireless device, a wired device and/or via plurality of
protocols. Also, the messages sent or received by any of the
modules may be sent or received directly and/or via one or more of
the other modules.
[0153] One skilled in the art will appreciate that a "system" could
be embodied as a personal computer, a server, a console, a personal
digital assistant (PDA), a cell phone, a tablet computing device, a
smartphone or any other suitable computing device, or combination
of devices. Presenting the above-described functions as being
performed by a "system" is not intended to limit the scope of the
present application in any way but is intended to provide one
example of many embodiments. Indeed, methods, systems and
apparatuses disclosed herein may be implemented in localized and
distributed forms consistent with computing technology.
[0154] It should be noted that some of the system features
described in this specification have been presented as modules, in
order to more particularly emphasize their implementation
independence. For example, a module may be implemented as a
hardware circuit comprising custom very large-scale integration
(VLSI) circuits or gate arrays, off-the-shelf semiconductors such
as logic chips, transistors, or other discrete components. A module
may also be implemented in programmable hardware devices such as
field programmable gate arrays, programmable array logic,
programmable logic devices, graphics processing units, or the
like.
[0155] A module may also be at least partially implemented in
software for execution by various types of processors. An
identified unit of executable code may, for instance, comprise one
or more physical or logical blocks of computer instructions that
may, for instance, be organized as an object, procedure, or
function. Nevertheless, the executables of an identified module
need not be physically located together but may comprise disparate
instructions stored in different locations which, when joined
logically together, comprise the module and achieve the stated
purpose for the module. Further, modules may be stored on a
computer-readable medium, which may be, for instance, a hard disk
drive, flash device, random access memory (RAM), tape, or any other
such medium used to store data.
[0156] Indeed, a module of executable code could be a single
instruction, or many instructions, and may even be distributed over
several different code segments, among different programs, and
across several memory devices. Similarly, operational data may be
identified and illustrated herein within modules and may be
embodied in any suitable form and organized within any suitable
type of data structure. The operational data may be collected as a
single data set or may be distributed over different locations
including over different storage devices, and may exist, at least
partially, merely as electronic signals on a system or network.
[0157] It will be readily understood that the components of the
application, as generally described and illustrated in the figures
herein, may be arranged and designed in a wide variety of different
configurations. Thus, the detailed description of the embodiments
is not intended to limit the scope of the application as claimed
but is merely representative of selected embodiments of the
application.
[0158] One having ordinary skill in the art will readily understand
that the above may be practiced with steps in a different order,
and/or with hardware elements in configurations that are different
than those which are disclosed. Therefore, although the application
has been described based upon these preferred embodiments, it would
be apparent to those of skill in the art that certain
modifications, variations, and alternative constructions would be
apparent.
[0159] While preferred embodiments of the present application have
been described, it is to be understood that the embodiments
described are illustrative only and the scope of the application is
to be defined solely by the appended claims when considered with a
full range of equivalents and modifications (e.g., protocols,
hardware devices, software platforms etc.) thereto.
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