Document Security: Wikipedia

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Document Security
• Terms, Definition, and Aspects
• Paradigms for Document Security
• Example: Guilloche Pattern as Security
Feature (SF)
• Problems for Reproduction of SF
• Security Techniques for Documents
• Publicity Levels
Document Security: Wikipedia
A document contains information. It often refers to an actual product of
writing or recording and is usually intended to communicate or store
collections of data. Documents are often the focus and concern of business
administration and government administration. The word is also used as a
verb as "documenting" describes the process of making a document.
The term document may be applied to any discrete representation of
meaning, but usually it refers to something physical like one or more printed
pages, or to a "virtual" document in electronic (digital) format.
Documents: Aspects
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Types of documents: paper-based, electronic
More general: media
Documents have content, layout, mark-up
Electronic2paper: printing, but
paper2electronic: pattern recognition
Security documents are a subclass of
documents (like travel documents,
application forms, personal documents)
Authentication vs. Authorization
Document security applies to more media
than “just” documents...
Also documents...
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packings of products (software box, drugs)
coins
stamps
logfiles of server
Terms
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Creating a new false document from scratch:
a forgery
Modifying an existing one: to tamper
Imitating a brand product: to fake, a fraud
By-passing a security means: deception, to
deceive
Attempt to by-pass a security means is
usually called an attack, or more friendly a
counterfeit
Document Security: Means
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Security printing techniques
Cryptography
Security procedures
Biometrics (esp. handwriting examination)
Public awareness, law enforcement
Main paradigms of (traditional)
document security
• Effort contest: Make the effort for producing a
forgery higher than the benefit of making such a
forgery.
• Personalization: Attach unique features for a class
of documents, or even single documents.
• Publicity: Make security features partially known
to the public.
Guilloche Patterns
• initially an engraving technique,
known use since 17th century
• named after French engineer
Guillot
• most common security pattern,
usually associated with “official
documents” (e.g. nearly each
banknote in the world has such
patterns)
Formerly: Guilloche Machines
Today: Guilloche Software
example: Excentro for MacOS...
Guilloche: Basic Principle
Guilloche: Why is it secure?
• protection against copying: problems are color
gamut, half-toning, multi-chip cameras,
geometric distortions (explained next)
• protection against re-origination: many
parameters, “secret” formula
• specific protections: in practice, there are often
two overlapping Guilloche patterns used (darker
and lighter), so a copy device cannot sense
contrast in both parts with sufficient accurracy
• “social” protection: by producer agreement, each
color copier will refuse to copy banknotes
Problem 1: Color Gamut
Typical technical devices
(printer, scanner, monitor,
copier, camera) can only
cover part of the spectrum
of colors, which can be
perceived by the human
eye. This part is called
gamut of the device.
For example, a printer can
print a color, which cannot
be sensed by the CCD-line
camera of a scanner.
Problem 2: Half-Toning
Printer can only place single points on paper. So-called dithering algorithms (there are
many) convert gayscale information into a point raster.
Problem 3: Multi-Chip Cameras
A normal (CCD or CMOS) camera chip can
only sense intensities of light (by collecting
over some period). Thus, for each color
channel (red, green, blue) there has to be a
separate chip.
In a scanner’s camera, the elements for
different colors are placed next to each other
(like RGBRGBRGB...), so there is always a
small offset between the color information.
Algorithms like Bayer Filter can combine this
information into color information for each
pixel.
However, the fine lines and details of a Guilloche pattern cannot be compensated by
such methods.
Problem 4: Geometric
distortions
All problems together...
Part of original DM100 banknote, and two attempts to make a copy.
Main paradigms of (traditional)
document security - Repeated
• Effort contest: Make the effort for producing a
forgery higher than the benefit of making such a
forgery.
• Personalization: Attach unique features for a class
of documents, or even single documents.
• Publicity: Make security features partially known
to the public.
Security Printing Techniques
Main categories of security features:
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substrate-based security
special printing inks and techniques
security pattern based
diffusion-based security features
interference-based security features
Substrate-based SF
•watermarks
•chemical reactants
•mechanical (feel)
•fluorescence
•tints
•security fibers
•planchets
•perforation
Substrate-based SF
•watermarks
•chemical reactants
•mechanical (feel)
•fluorescence
•tints
•security fibers
•planchets
•perforation
Substrate-based SF
•watermarks
•chemical reactants
•mechanical (feel)
•fluorescence
•tints
•security fibers
•planchets
•perforation
Special Printing Inks and
Techniques
•photosensitive inks
•thermochromatic inks
•metameric inks
•iridescent inks
•magnetic inks
•intaglio print
Special Printing Inks and
Techniques
•photosensitive inks
•thermochromatic inks
•metameric inks
•iridescent inks
•magnetic inks
•intaglio print
Special Printing Inks and
Techniques
•photosensitive inks
•thermochromatic inks
•metameric inks
•iridescent inks
•magnetic inks
•intaglio print
Special Printing Inks and
Techniques
•photosensitive inks
•thermochromatic inks
•metameric inks
•iridescent inks
•magnetic inks
•intaglio print
Security Patterns
•Guilloche
•Microprint
•See-through register
•Latent images
•Scan traps
•Covert watermarks
Microprint, and scan-copy
Security Patterns
•Guilloche
•Microprint
•See-through register
•Latent images
•Scan traps
•Covert watermarks
Security Patterns
•Guilloche
•Microprint
•See-through register
•Latent images
•Scan traps
•Covert watermarks
Diffraction-based SF
also named OVD (optically variable
device)
•gold foil
•hologram
•kinegram
Diffraction-based SF
also named OVD (optically variable
device)
•gold foil
•hologram
•kinegram
Diffraction-based SF
also named OVD (optically variable
device)
•gold foil
•hologram
•kinegram
Interference-based SF
•optically-variable ink (OVI)
•hologram overlay
•Lippmann photo
Interference-based SF
•optically-variable ink (OVI)
•hologram overlay
•Lippmann photo
Interference-based SF
•optically-variable ink (OVI)
•hologram overlay
•Lippmann photo
Lippmann photo: Technique for taking a photo and inverted
photo at the same time.
More information:
Rudolf L. van Renesse
“Optical Document Security” (3rd Edition)
Artech House Boston, London
Main paradigms of (traditional)
document security - Repeated
• Effort contest: Make the effort for producing a
forgery higher than the benefit of making such a
forgery.
• Personalization: Attach unique features for a class
of documents, or even single documents.
• Publicity: Make security features partially known
to the public.
Publicity Levels
1. Class: Security features are distributed
about public channels (media, internet,
hand-out)
2. Class: Security features are only known to
trained personal, but nevertheless they are
no general secret
3. Class: Security features are only known to a
small group, and its distribution may be even
illegal.
1000 Yen Banknote
Source http://www.boj.or.jp/en/type/release/zuiji/kako03/bnnew3.htm
1000 Yen Banknote
Security Features (1)
(1) Latent pearl image
A security feature unique to the new
1,000 yen note. When the banknote is
tilted, you can see (1) the Japanese
characters meaning "1,000 yen"
printed with pearl ink, and (2) the
number "1000" as a latent image.
Security Features (2)
(2) Watermark-bar-pattern
When the banknote is held up to the
light, a vertical watermark bar (three
bars for the 10,000 yen note, two for
the 5,000 yen note) becomes visible.
This feature is more difficult to
reproduce with personal computers or
color copiers than the traditional
watermark.
Security Features (3)
(3) Latent image
When the banknote is viewed from a
certain angle, the word "NIPPON"
("Japan" in Japanese) appears on the
top right of the back side.
Security Features (4)
(4) Pearl ink
When viewed from different angles, a
semi-transparent pattern printed with
pink pearl ink appears in the blank
areas of the left and right margins of
the front of the note.
Security Features (5)
(5) Microprinting
Like notes issued since December 1,
1993 (with serial numbers in brown or
dark green), the new 1,000 yen note
has the words "NIPPON GINKO"
("Bank of Japan" in Japanese) printed
in micro letters. Some of the micro
letters are made even smaller on the
new note than those on the current
note. Also, micro letters of different
sizes are included in the background
design.
(6) Luminescent ink
As in notes issued since December 1,
1993 (with serial numbers in brown or
dark green), the Governor's seal on
the front side glows orange under
ultraviolet light. Likewise, some parts
of the background pattern fluoresce
yellowish-green.
Security Features (7)
(7) Intaglio printing
Raised printing is used for some features
of the new note. The ink on the new
note is raised higher than the ink on
the current note.
Security Features (8)
(8) Tactile marks (intaglio printing)
To assist the visually impaired in
detecting the note by touch, a
recognition symbol with a rougher
texture, printed intaglio, is adopted
instead of the watermark symbols
used for the current note.
Undocumented Features
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