U.S. patent application number 09/683368 was filed with the patent office on 2002-07-11 for hidden information on a document for authentication.
This patent application is currently assigned to Pitney Bowes Inc.. Invention is credited to Dlugos, Daniel F..
Application Number | 20020088866 09/683368 |
Document ID | / |
Family ID | 27103087 |
Filed Date | 2002-07-11 |
United States Patent
Application |
20020088866 |
Kind Code |
A1 |
Dlugos, Daniel F. |
July 11, 2002 |
HIDDEN INFORMATION ON A DOCUMENT FOR AUTHENTICATION
Abstract
A method and system for authenticating a postage indicium on a
mail piece. The method comprises the steps of providing a first
pattern containing encrypted information in a printed area,
engaging a mask with the printed area, wherein the mask comprises a
second pattern for forming with the first pattern a third pattern
indicative of the encrypted information. The method further
comprises the step of comparing the third pattern with a template
having stored information. If the encrypted information revealed in
the third pattern matches the stored information, then the postage
indicium is assumed to be an original copy and not a duplicated
copy.
Inventors: |
Dlugos, Daniel F.;
(Huntington, CT) |
Correspondence
Address: |
PITNEY BOWES INC.
35 WATERVIEW DRIVE
P.O. BOX 3000
MSC 26-22
SHELTON
CT
06484-8000
US
|
Assignee: |
Pitney Bowes Inc.
|
Family ID: |
27103087 |
Appl. No.: |
09/683368 |
Filed: |
December 19, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09683368 |
Dec 19, 2001 |
|
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09741496 |
Dec 19, 2000 |
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Current U.S.
Class: |
235/494 |
Current CPC
Class: |
G07F 7/12 20130101; G07B
2017/00443 20130101; G07B 2017/00201 20130101; G07B 17/00508
20130101; G07B 2017/00637 20130101; G07F 7/08 20130101 |
Class at
Publication: |
235/494 |
International
Class: |
G06K 019/06 |
Claims
1. A method of authenticating a postage indicium on a mail piece
having a printed area, said method comprising the steps of: (a)
providing a first pattern containing encrypted information in the
printed area; and (b) engaging a decryption mechanism with the
printed area, wherein the decryption mechanism comprises a second
pattern for forming with the first pattern a third pattern
indicative of the encrypted information.
2. A method of authenticating a mark on a document having a printed
area, said method comprising the steps of: (a) providing a first
pattern containing encrypted information in the printed area; and
(b) engaging a decryption mechanism with the printed area, wherein
the decryption mechanism comprises a second pattern for forming
with the first pattern a third pattern indicative of the encrypted
information.
3. The method of claim 2, wherein the first pattern comprises a
first line pattern, the second pattern comprises a second line
pattern and the third pattern comprises a third line pattern.
4. The method of claim 2, wherein the third line pattern comprises
fringes separated by spacings, and wherein the spacings are
indicative of the encrypted information.
5. The method of claim 2, wherein the third line pattern comprises
a Moir pattern.
6. The method of claim 2, wherein the first pattern comprises a
first color pattern, the second pattern comprises a second color
pattern for color-filtering the first color pattern, and the third
pattern comprises a color-filtered pattern indicative of the
encrypted information.
7. The method of claim 6, wherein the first color pattern comprises
a first plurality of color patches of a first color and a second
color complementary to the first color, and the second pattern
comprises a second plurality of color patches of the first color
and the second color, and wherein a third color is formed when a
color patch of the first color is superimposed on a color patch of
the second color, and the color-filtered pattern comprises a third
pattern comprising a third plurality of color patches of the third
color.
8. The method of claim 2, wherein the first pattern comprises a
pattern of dots and the second pattern comprises a plurality of
windows for observing the dots.
9. The method of claim 8, wherein the dots have at least a first
color and the third pattern comprises a plurality of dots having a
second color indicative of the first color.
10. The method of claim 9, wherein the windows have a color filter
to filter the first color.
11. The method of claim 2, further comprising the step of
converting the first pattern into an electronic pattern, wherein
the decryption mechanism comprises an electronic mask indicative of
the second pattern for electronically processing the electronic
pattern.
12. The method of claim 2, wherein the electronic pattern comprises
a bit-map.
13. The method of claim 12, wherein the electronic mask comprises a
bit-map.
14. The method of claim 13, wherein the electronic mask is
computer-generated.
15. The method of claim 2, wherein the first pattern is provided on
the document.
16. The method of claim 2, wherein the printed area further
comprises a message area and the first pattern is provided on the
message area.
17. The method of claim 2, further comprising the steps of: (a)
storing information indicative of the encryption information; and
(b) comparing the stored information with the third pattern for
authenticating the mark based on said comparison.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part of U.S. patent application
Ser. No. 09/741,496 entitled "Hidden Information On A Mail Piece
For Authentication" filed Dec. 19, 2000, incorporated herein by
reference.
BACKGROUND OF INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to producing a
postage indicium and other text or images on a mail piece and, more
particularly, to a method and system for authenticating the postage
indicium.
[0004] 2. Background of the Invention
[0005] Postage metering systems have been developed which employ
encrypted information that is printed on a mail piece as part of an
indicium-evidencing postage payment. The encrypted information
includes a postage value for the mail piece, combined with other
postal data that relate to the mail piece and the postage meter
printing the indicium. The encrypted information, typically
referred to as a digital token or a digital signature,
authenticates and protects the integrity of information, including
the postage value, imprinted on the mail piece for later
verification of postage payment. Since the digital token
incorporates encrypted information relating to the evidencing of
postage payment, altering the printed information in an indicium is
detectable by standard verification procedures. Examples of systems
that generate and print such indicium are described in U.S. Pat.
Nos. 4,725,718; 4,757,537; 4,775,246 and 4,873,645, each assigned
to the assignee of the present invention.
[0006] Presently, there are two postage metering device types: a
closed system and an open system. In a closed system, the system
functionality is solely dedicated to metering activity. Examples of
closed-system metering devices, also referred to as
postage-evidencing devices, include conventional digital and analog
(mechanical and electronic) postage meters, wherein a dedicated
printer is securely coupled to a metering or accounting function.
In a closed system, typically, the printer is securely coupled and
dedicated to the meter, and printing evidence of postage cannot
take place without accounting for the evidence of postage. In an
open system, the printer is not dedicated to the metering activity,
freeing system functionality for multiple and diverse uses in
addition to the metering activity. Examples of open system metering
devices include personal-computer (PC) based devices with
single/multi-tasking operating systems, multi-user applications and
digital printers. An open-system metering device is a
postage-evidencing device with a non-dedicated printer that is not
securely coupled to a secure accounting module. An open-system
indicium printed by the non-dedicated printer is made secure by
including addressee information in the encrypted evidence of
postage printed on the mail piece for subsequent verification. See
U.S. Pat. Nos. 4,725,718 and 4,831,555, each assigned to the
assignee of the present invention.
[0007] The United States Postal Service (USPS) has proposed an
Information-Based Indicia Program (IBIP), which is a
distributed-trusted system to retrofit and augment existing postage
meters, using new evidence of postage payment known as
information-based indicia. The program relies on digital signature
techniques to produce for each envelope an indicium whose origin
can be authenticated and content cannot be modified. IBIP is
expected to support new methods of applying postage in addition to
the current approach, which typically relies on a postage meter to
print indicia on mail pieces. IBIP requires printing a large, high
density, two-dimensional (2-D) bar code on a mail piece. The 2-D
bar code encodes information and is signed with a digital
signature.
[0008] The USPS has published draft specifications for IBIP. The
INFORMATION-BASED INDICIA PROGRAM (IBIP) INDICIUM SPECIFICATION,
dated Jun. 13, 1996, and revised Jul. 23, 1997, (IBIP Indicium
Specification) defines the proposed requirements for a new indicium
that will be applied to mail being created using IBIP. The
INFORMATION-BASED INDICIA PROGRAM POSTAL SECURITY DEVICE
SPECIFICATION, dated Jun. 13, 1996, and revised Jul. 23, 1997,
(IBIP PSD Specification) defines the proposed requirements for a
Postal Security Device (PSD), which is a secure processor-based
accounting device that dispenses and accounts for postal value
stored therein to support the creation of a new information-based
postage postmark or indicium that will be applied to mail being
processed using IBIP. The INFORMATION-BASED INDICIA PROGRAM HOST
SYSTEM SPECIFICATION, dated Oct. 9, 1996, defines the proposed
requirements for a host-system element of IBIP (IBIP Host
Specification). IBIP includes interfacing user, postal and vendor
infrastructures, which are the system elements of the program. The
INFORMATION-BASED INDICIA PROGRAM KEY MANAGEMENT PLAN
SPECIFICATION, dated Apr. 25, 1997, defines the generation,
distribution, use and replacement of the cryptographic keys used by
the USPS product/service provider and Pad's (IBIP KMS
Specification). These specifications have been consolidated into
one specification entitled PERFORMANCE CRITERIA FOR INFORMATION
BASED INDICIA AND SECURITY ARCHITECTURE FOR OPEN IBI POSTAGE
EVIDENCING SYSTEMS (PCIBI-0), dated Feb. 23, 2000. The
specifications are collectively referred to herein as the IBIP
Specifications.
[0009] The IBIP Specifications define a stand-alone, open-metering
system, referred to herein as a PC Meter, comprising a PSD coupled
to a personal computer (PC) which operates as a host system with a
printer coupled thereto (Host PC). The Host PC runs the metering
application software and associated libraries (collectively
referred to herein as Host Applications) and communicates with one
or more attached PSD's. The PC Meter can only access PSD's coupled
to the Host PC. There is no remote PSD access for the PC Meter.
[0010] The PC Meter processes transactions for dispensing postage,
registration and refills on the Host PC. Processing is performed
locally between the Host PC and the PSD coupled thereto.
Connections to a data center, for example, for registrations and
refill transactions, are made locally from the Host PC through a
local or network modem/internet connection. Accounting for debits
and credits to the PSD is also performed locally, logging the
transactions on the Host PC. The Host PC may accommodate more than
one PSD, for example, supporting one PSD per serial port. Several
application programs running on the Host PC, such as a word
processor or an envelope designer, may access the Host
Applications.
[0011] The IBIP Specifications do not address an IBIP open-metering
system on a network environment. However, the specifications do not
prohibit such a network-based system. Generally, in a network
environment, a network server controls remote printing requested by
a client PC on the network. Of course, the client PC controls any
local printing.
[0012] One version of a network metering system, referred to herein
as a virtual postage metering system, has many Host PCs without any
PSD's coupled thereto. The Host PC's run Host Applications, but all
PSD functions are performed on server(s) located at a data center.
The PSD functions at the data center may be performed in a secure
device attached to a computer at the data center, or may be
performed in the Data center computer itself. The Host PCs must
connect with the data center to process transactions such as
postage dispensing, meter registration, or meter refills.
Transactions are requested by the Host PC and sent to the data
center for remote processing. The transactions are processed
centrally at the data center, and the results are returned to the
Host PC. Accounting for funds and transaction processing are
centralized at the data center. See, for example, U.S. Pat. Nos.
4,873,645 and 5,454,038, which are assigned to the assignee of the
present invention.
[0013] In U.S. Pat. Nos. 4,873,645 and 5,454,038, a virtual postage
metering system and method are disclosed, wherein the postal
accounting and token generation occur at a data center remote from
the postage-evidencing printer. Although the data center may be a
secure facility, there remain certain inherent security issues
since the accounting and token generation functions do not occur in
a secure device local to the postage printer. The virtual postage
metering system includes a computer coupled to an unsecured printer
and to a remote data metering system. The postal accounting and the
token generation occur at the data center.
[0014] The data center is a centralized facility under the control
of a meter vendor, such as Pitney Bowes, or the Postal Service. As
such, it is regarded as secure compared to the environment where
mailers handle meters directly. However, data stored at the data
center is accessible to data center personnel and, therefore, at a
minimum, subject to at least inadvertent modification by such
personnel. Any unauthorized changes to the user and meter data
stored at the data center compromises the integrity of the virtual
postage metering system.
[0015] Furthermore, in the mail piece security system based on
digital indicia, if the postage indicium is duplicated and produced
on more than one mail piece, it is very difficult for the Postal
Service to tell which, among the mail pieces having identical
indicium, has the original indicium. Thus, it is advantageous and
desirable to provide a method and a system for authenticating the
indicium.
[0016] Other forms of authentication systems have been utilized by
the prior art. For instance, document authentication systems have
been developed. (As used herein the term "documents" refers to
items, including but not limited to, currency, financial
instruments, tickets, deeds, contracts, other legal documents,
collectables, passports and visas, etc., which bear information and
which have an inherent value distinct from the value of the
information they bear, and/or are evidence of a right or immunity
possessed by the proper holder of such documents.) One of the
problems of the prior art is to produce documents that are secure
against counterfeiting, and a method for authenticating such
documents.
SUMMARY OF INVENTION
[0017] It is a primary object of the present invention to provide
on a mail piece a postage indicium and encryption information that
can be produced by a closed postage metering device, such as
postage meter, or an open postage metering system, such as a
personal-computer based device connected to a digital printer,
wherein the encryption information is provided within the postage
indicium or other areas on the mail piece so that the indicium can
be authenticated based on the encryption information. Accordingly,
the first aspect of the present invention is a method for
authenticating a postage indicium on a mail piece. The method
comprises the steps of: providing a first pattern containing hidden
information in a printed area on the mail piece; and engaging a
masking mechanism with the printed area for observing the first
pattern, wherein the masking mechanism has a second pattern for
forming with the first image a third pattern indicative of the
hidden information.
[0018] It is possible that the first pattern comprises a first line
pattern, the second pattern comprises a second line pattern and the
third pattern comprises a Moir pattern.
[0019] It is possible that the first pattern comprises a first
color pattern, the second pattern comprises a second color pattern
for color-filtering the first pattern, and the third pattern
comprises a color-filtered pattern indicative of the hidden
information.
[0020] It is possible that the first pattern comprises a pattern of
dots, the second pattern comprises a plurality of windows for
observing the dots, and the third pattern comprises a further
pattern of dots indicative of the hidden information.
[0021] It is possible that the first pattern is electronically
filtered for providing a first electronic pattern and second
pattern is electronically produced, wherein the second pattern and
the first electronic pattern are electronically compared for
producing the third pattern.
[0022] Preferably, the first pattern is provided within the postage
indicium, but it is possible to produce the first pattern on the
mail piece outside the postage indicium.
[0023] The second aspect of the present invention is a system for
authenticating a postage indicium on a mail piece. The system
comprises: a mechanism for providing on a printed area a first
pattern containing hidden information; and a masking mechanism, for
engaging with the printed area for observing the first pattern,
wherein the masking mechanism comprises a second pattern for
forming with the first image a third pattern indicative of the
hidden information.
[0024] It is another object of the present invention to provide on
a document a mark and encryption information that can be produced
by a closed metering device, such as a postage meter, or an open
metering system, such as a personal-computer based device connected
to a digital printer, wherein the encryption information is
provided within the mark or other areas on the document so that the
mark can be authenticated based on the encryption information.
Accordingly, an aspect of the present invention is a method for
authenticating a mark on a document. The method comprises the steps
of providing a first pattern containing hidden information in a
printed area on the document; and engaging a masking mechanism with
the printed area for observing the first pattern, wherein the
masking mechanism has a second pattern for forming with the first
image a third pattern indicative of the hidden information.
[0025] The present invention will become apparent upon reading the
description taken in conjunction with FIGS. 1 to 9.
BRIEF DESCRIPTION OF DRAWINGS
[0026] FIG. 1 is a diagrammatic representation illustrating a
system for authenticating a mail piece, according to the present
invention.
[0027] FIG. 2 is a diagrammatic representation illustrating a
typical postage indicium containing hidden information.
[0028] FIG. 3a is a diagrammatic representation illustrating a
proposed 2D postage indicium containing hidden information.
[0029] FIG. 3b is a diagrammatic representation illustrating a line
pattern containing the hidden information provided on the 2D
postage indicium.
[0030] FIG. 3c is a diagrammatic representation illustrating a
variation of the line pattern for changing the hidden information
provided on the 2D postage indicium.
[0031] FIG. 4a is a diagrammatic representation illustrating a
decryption mask being used on a line pattern containing encryption
information for revealing the information.
[0032] FIG. 4b is a diagrammatic representation illustrating the
same decryption mask being used on a slightly different line
pattern, revealing different encrypted information.
[0033] FIG. 5a is a diagrammatic representation illustrating a
color pattern being used to conceal information.
[0034] FIG. 5b is a diagrammatic representation illustrating a
color filter being used as a decryption mask for color filtering
the color pattern of FIG. 5a for revealing the information
concealed in the color pattern.
[0035] FIG. 5c is a diagrammatic representation illustrating the
information revealed by the decryption mask of FIG. 5b.
[0036] FIG. 6a is a diagrammatic representation illustrating a
pattern of color dots being used to conceal information.
[0037] FIG. 6b is a diagrammatic representation illustrating a
see-through being used as a decryption mask for observing the dots
in the dot pattern of FIG. 6a for revealing the information
concealed in the dot pattern.
[0038] FIG. 6c is a diagrammatic representation illustrating the
information revealed by the decryption mask of FIG. 6b.
[0039] FIG. 6d is a diagrammatic representation illustrating
another see-through mask with a color filter being used as a
decryption mask for observing the dots in the dot pattern of FIG.
6a for revealing further information concealed in the dot
pattern.
[0040] FIG. 6e is a diagrammatic representation illustrating the
information revealed by the decryption mask of FIG. 6d.
[0041] FIG. 7a is a diagrammatic representation illustrating a
bit-map resulting from electronic filtering.
[0042] FIG. 7b is a diagrammatic representation illustrating
another bit-map being used as a decryption mask for revealing the
information concealed in the bit-map of FIG. 7a.
[0043] FIG. 7c is a diagrammatic representation illustrating the
information revealed by the decryption mask of FIG. 7b.
[0044] FIG. 8 is a flow chart illustrating the method of providing
encryption on a mail piece for authentication purposes, according
to the present invention.
[0045] FIG. 9 is a diagrammatic representation illustrating a
system for authenticating a document, according to the present
invention.
DETAILED DESCRIPTION
[0046] FIG. 1 illustrates a system 1 for verifying a mail piece
100, according to the present invention. As shown, the system 1
include a postage meter 10 having a print head 12 for printing a
postage indicium 110, a return address 140, a mailing address 142
or a promotional message 150 on the mail piece 100. In order to add
security to the mail piece, hidden or encryption information can be
provided on the mail piece 100. As shown in FIGS. 2 to 3c, the
encryption information can be concealed in a pattern provided
within the postage indicium 110. However, the encryption
information can be concealed in a pattern (FIG. 5a, for example)
provided on the return address 140, the mailing address 142, the
promotional message 150 or other area on the mail piece 100,
preferably in an inconspicuous fashion. Instead of the postage
meter 10, a printer 22 can be connected to a Personal Computer (PC)
20 to print images or text on the mail piece 100. When the mail
piece 100 reaches a data center 200, a decryption mechanism 210 is
used to reveal the information 220 concealed in the pattern. The
data center 200 has a template 230 containing data or images
indicative of the information 220 to allow a comparison mechanism
240 to compare the information 220 as revealed by the decryption
mechanism 210 to that provided in the template 230. If the
comparison is successful, it can be assumed that the postage
indicium 110 is not a duplicated copy. Along with other standard
verification procedures, as mentioned in the background section,
the encryption information can be used to authenticate the postage
indicium 110.
[0047] Postage indicia are well known. As shown in FIG. 2, the
postage indicium 110 can contain encryption information in
different areas of the indicium 110, such as the wing section 112
and the body 114 of the bald eagle symbol. Preferably, the
encryption information is provided on the mail piece in a seemingly
innocuous fashion. The encryption information, as shown in FIG. 2,
is hidden in a line pattern resembling the feather. Similarly,
encryption information can be provided on a 2D postage indicium
110', as shown in FIG. 3a.
[0048] As shown in FIG. 3a, the line pattern is provided on a
section 116 of the bald eagle symbol. Preferably, the line pattern
is extremely fine so that the line pattern is difficult to be
reproduced with an image scanner or a photocopier. The detail of
the line pattern on the section 116 is shown in FIG. 3b. As shown,
the line pattern in the section 116 contains closely spaced,
parallel straight lines 118. Preferably, the line pattern in one
indicium is slightly different from another so that the hidden
information in one indicium is different from the hidden
information in another indicium. For example, the parallel lines
118 in the section 116 for one indicium has a certain orientation,
or slope, as shown in FIG. 3b. In another indicium, the
orientation, or slope, of the parallel lines 118' are slightly
different, as shown in FIG. 3c. The difference in the slope can be
detected by using a mask having another line pattern. It is well
known that when a closely-spaced line pattern is superimposed with
another similarly spaced line pattern, a Moir pattern is formed, as
shown in FIGS. 4a and 4b. As shown in FIG. 4a, a mask 124
containing another line pattern is used as the decryption mechanism
170 (FIG. 1) to reveal the information hidden in a line pattern
120. The hidden information, in this case, is the fringe spacing S
of the Moir pattern 122. Accordingly, the template 230 (FIG. 1) can
contain an image similar to the Moir pattern 122 or data indicative
of the spacing S so as to allow the comparison mechanism 240 (FIG.
1) to compare the Moir pattern 122 based on the fringe spacing S.
In general, a slight change in the slope of the line pattern 120,
relative to the slope of the line pattern in the mask 124, can
result in a noticeable change in the fringe spacing S of the Moir
pattern 122. For example, the line pattern 120 can be rotated in
the counter-clockwise direction by a small angle to become the line
pattern 120', as shown in FIG. 4b. To the naked eyes, the line
pattern 120'seem to be identical to the line pattern 120. However,
using the same mask 124 to superimpose on the line pattern 120',
one can find that the fringe spacing S of the Moir pattern 122' is
considerably smaller than the fringe spacing 5 of the Moir pattern
122.
[0049] FIGS. 5a-5c illustrate another form of pattern which can be
used to contain encryption information. For example, a color
pattern 126 consisting of a plurality of square pixels 132 and 134
is used to contain the encrypted information, as shown in FIG. 5a.
Preferably, the color of the square pixels 132 is complementary to
the color of the square pixels 134. For example, the colors of the
pixels 132 and 134 can be, respectively, blue and yellow, or green
and magenta. Preferably, the colors of these pixels are very light
so that the color pattern 126 can be provided as an inconspicuous
background for the return address 140 or the mailing address 142
(FIG. 1), for example. A very light color pattern makes it more
difficult to duplicate by a photocopier. By itself, the color
pattern 126 does not show any recognizable pattern. It is well
known that when a color patch in light blue is superimposed on a
color patch of light yellow, the resultant color is gray. Thus,
when a mask 128 containing a plurality of square pixels 132 and
134, as shown in FIG. 5b, is used as a decryption mechanism 220
(FIG. 1) to color filter the color pattern 126, the resulting image
reveals an easily recognizable pattern, as shown in FIG. 5c. In
this case, the information hidden in the color pattern 126 and
revealed by the mask 128 is a rectangle 130 of fourteen gray pixels
standing out from patches of complementary colors. Accordingly, the
template 230 (FIG. 1) can contain a similar rectangular pattern or
contain data indicative of such a rectangle.
[0050] FIG. 6a shows a dot pattern 160 having dots of two colors to
conceal information. Dots of one color are denoted by reference
numeral 162 and dots of the other color are denoted by reference
numeral 164. As shown in FIG. 6a, the dots are organized in an
orderly fashion. However, it is possible that the dots are randomly
distributed. In order to reveal the concealed information, it is
possible to use a see-through mask 170, which is basically an
opaque plate having a plurality of see-through windows 172, as
shown in FIG. 6b. When the mask 170 is laid on top of the dot
pattern 160, it is expected that all the dots seen through the
windows 172 are of the same color, as shown in FIG. 6c. As shown in
FIG. 6c, the heart-shaped pattern 166 is composed only of color
dots 164. For example, if the color of the dots 164 is red and the
color of the dots 162 is cyan, then the hidden information is a
heart of red dots only. Accordingly, the template 230 (FIG. 1) can
simply be a red color filter for picking out any cyan dots in the
revealed heart. As shown in FIG. 6b, the decryption mask 170 also
shows the heart-shaped pattern similar to the revealed information.
However, the pattern in the decryption mask can be different from
the pattern in the revealed information. For example, the windows
174 in the mask 170", as shown in FIG. 6d, are covered with a red
color filter to pick out the cyan dots 162 within the window area.
When the mask 170" is laid on top of the dot pattern 160,
information revealed by the mask 170" is a question mark 168
composed of black or gray dots 162', as shown in FIG. 6e. In this
case, the pattern in the mask 170" is not the same as the pattern
in the revealed information.
[0051] It should be noted that the masks 128 (FIG. 5b), 170 (FIG.
6b) and 170" (FIG. 6d) are physical masks. These masks must be
physically put on top of a printed pattern to reveal what is
hidden. However, it is possible to use an image scanner to scan the
printed pattern and electronically process the scanned image into a
bit-map so that a computer-generated mask can be used to
electronically filter the bit-map to reveal the hidden information.
For example, it is possible to turn the pattern 126, as shown in
FIG. 5a, into a bit-map 180, as shown in FIG. 7a. As shown in FIG.
7a, color patches 132 are electronically filtered to become pixels
containing the value of 1, and color patches 134 are converted into
pixels containing the value of 0. The bit-map 180 is represented by
a square array of pixels (m,n) having pixel values l(m,n), where
m,n=1 to 14. In order to reveal the hidden information in this
square array, it is possible to use a computer-generated mask 182
to electronically filter the bit-map 180. For example, a square
array of pixels (u,v) having pixel values j (u,v) where u,v=1 to 7,
as shown in FIG. 7b can be used to electrically filter the bit-map
780 using an exclusive AND operation as follows: R(u,v)=l(m,n)
{circle over (x)} (u,v), with m=v+7, n=u+3, where R(u,v) is equal
to 1 only when l(m,n) is the same as J(u,v). Otherwise, R(u,v) is
equal to 0. For example, when u=1, v=2, m=8, n=5, we have J(1,2)=0,
1(8,5)=1 and R(1,2)=0. When u=2, v=2, m=9, v=5, we have J (2,2)=0,
1(9,5)=0 and R(2,2)=1. When u=3, v=2, m=10, u=5, we have J(3,2)=1,
1(10,5)=1 and R(3,2)=1. When u=3, v=3, m=10, n=6, we have J(3,3)=1,
1(10,6)=0 and R(3,3)=0. The bit-map 184 representing R(u,v) is
shown in FIG. 7c and the hidden information is a plurality of
pixels having the value of 1 forming a rectangle, similar to the
revealed information shown in FIG. 5c.
[0052] The method of providing encryption information on a mail
piece using a printer connected to a PC, or a postage meter having
a digital print head, according to the present invention, is
illustrated in a flow chart 400, as shown in FIG. 8. As shown, a
software program can be used to select an area on the mail piece
for providing the encryption or hidden information, at step 410.
The same software program can be used to select the encryption
information and the pattern to contain the encryption information,
at step 420. At step 430, the postage meter prints on the mail
piece an indicium and other information, along with the selected
pattern. Preferably, the selected pattern is printed in a rather
inconspicuous fashion so that the user of the meter does not notice
such a pattern. The encryption information is conveyed to a data
center at step 440, so that when the data center receive the mail
piece, it can use a mask or equivalent decryption mechanism to
reveal the hidden information, at step 450. The data center further
compares the revealed information at step 450 to a template at step
460. Based on the comparison, the data center can determine whether
the indicium is a duplicated copy or an original copy.
[0053] FIG. 9 is an embodiment of this invention that illustrates a
system 800 for verifying a document 700, according to the present
invention. As shown, the system 800 include a postage meter 810
having a print head 812 for printing a postage indicium or other
mark 110, and information 150 on the document 700. In order to add
security to the document, hidden or encryption information can be
provided on the document 700. As shown in FIGS. 2 to 3c, the
encryption information can be concealed in a pattern provided
within the mark 110. However, the encryption information can be
concealed in a pattern (FIG. 5a, for example) provided on
information 750 or other area on the document 700, preferably in an
inconspicuous fashion. Instead of the postage meter 810, a printer
722 can be connected to a Personal Computer (PC) 720 to print
images or text on the document 700. When the mail piece 700 reaches
a data center 200, a decryption mechanism 210 is used to reveal the
information 220 concealed in the pattern. The data center 200 has a
template 230 containing data or images indicative of the
information 220 to allow a comparison mechanism 240 to compare the
information 220 as revealed by the decryption mechanism 210 to that
provided in the template 230. If the comparison is successful, it
can be assumed that the mark 110 is not a duplicated copy. Along
with other standard verification procedures, as mentioned in the
background section, the encryption information can be used to
authenticate the mark 110.
[0054] The present invention has been described in regard to
concealing a pattern within a line pattern or a color pattern.
However, there are many more ways wherein a message can be
concealed within a text pattern or an image can be concealed within
another image. The disclosed methods are only intended to
demonstrate the principle of providing hidden information on a mail
piece for authentication purposes.
[0055] Thus, although the invention has been described with respect
to preferred embodiments thereof, it will be understood by those
skilled in the art that the foregoing and various other changes,
omissions and deviations in the form and detail thereof may be made
without departing from the spirit and scope of this invention.
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