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The police have been using digital equipment for a couple of years now. Because of the equipments superiour capabilities, with the appropriate budgets, simply too good to miss out on. Intelligence gathering operation and applications, taken together with the powerful databasing and facial recognition systems are becoming increasingly powerful tools.
A Picture is Worth a Thousand WordsThe tabloid at the supermarket check-out may have another "Elvis is Alive" story with a picture of him holding the last month's issue: inside there might be a story about a World War II Lancaster bomber landing on the moon, with photographs to prove it. But by and large people do not believe these photographs however real they look, and it is doubtful if the authors expect them to.
So why should people doubt the photographs in a broadsheet of the Chancellor of the Exchequer holding up his red box on Budget Day in front of No. 11 (The Guardian 3 July 1997)[1]? Even those who approach what is written with a reasonable degree of scepticism have a general presumption that a photograph is what it purports to be.
Further, if a jury in a criminal case is shown by the prosecution a clear and unambiguous photograph of the defendant caught in the act, in the absence of any other evidence, will the members regard it with just the same degree of scepticism as they had for the picture of the Lancaster on the moon? And should they?
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FIFTH REPORT - 3 February 1998 By the Select Committee appointed to consider Science and Technology. ORDERED TO REPORT |
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I offer yet another example of the use of Photoshop for 'political' purposes. When I was first introduced to Digital Manipulation, I was advised that it was worth considering the additional damage, that Joseph Gobels, propagander Minister of the Third Reich, could have done to history, if such technology had been available to him.
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An Osama bin Laden poster is displayed during an anti-U.S. demonstration in Dhaka, Bangladesh October 11, 2001. The poster shows Osama bin Laden together with the Sesame Street character Bert. Created from images available on the internet, this poster is sold by the thousand at Dhaka shops according to local traders. (Rafiqur Rahman/Reuters) |
The National Union of Journalist (NUJ), is trying to promote a scheme whereby any photograph or image used in a news context, is marked accordingly. This is vital for the integity of a news photographer
Manipulation now 'evident'The evidence value of digital photographs has been greatly enhanced by the development of software that will show whether images have been manipulated and identify the parts of an image that have been changed.
Witney, Oxfordshire-based software developer Signum Technologies
has created VeriData iDem, a specific application which will 'bag and tag'
images which may then be relied upon later in court as evidence, should
a case arise.
The software can show whether an image is original, or
has been changed.
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One of the leaders in this developing field is Signum Technologies. They have developed a product: - VeriData data validation technology. They say:-
The digital revolution has brought many benefits to the way we gather, manage and provide information.
As we begin to adopt digital technologies, the issue arises of how to safeguard the integrity and authenticity of digital records which may be required to stand up to judicial or ethical scrutiny.
Signum Technologies' innovative VeriData data validation technology is designed to address this issue by ensuring the integrity of digital visual or audio data at the point of creation or acquisition by providing a highly secure validated master reference file.
The essence of the VeriData process involves a checksum process where precisely calculated but indiscernible 'patterns' are embedded within digital image, video film, or audio recording data. If a data file which has been validated by the VeriData process is subsequently modified in any way, the VeriData detector software will detect the altered pattern. Any changes will be graphically highlighted or alternatively, flagged within a processing system. A confirmation of data integrity will be displayed or flagged where the data file remains intact and unchanged.
Importantly, this is achieved without compromising the quality of the underlying information, increasing the data file size or adding extraneous metadata such as digital signatures.
VeriData was developed with security and law-enforcement applications in mind. It goes without saying therefore, that VeriData is highly secure and incorporates special features to prevent the validation from being applied or undone by an unauthorised agency.
For added peace-of-mind, VeriData software will also allow you to 'tag' your records with information such as the date of acquisition and an administration reference. Once embedded, this hidden provenance information can only be revealed and decoded by corresponding VeriData reader software - it cannot be overwritten or modified without such changes being made obvious. For extra versatility, the embedded data may also be recovered from the printed output (hardcopy) derived from your VeriData tagged digital files.
VeriData currently allows the validation of a diverse range of recorded image data such as bitonal (1-bit) bank document images, 12-bit latent fingerprint images, radiographic images and digital audio recordings as well as more usual 4, 6 and 8-bit continuous tone colour and monochrome images. Signum has plans to support digital video formats in the near future.
Law Enforcement & Evidential Imaging:
Growth in the use of digital imaging in law-enforcement is rapid as new technologies - digital cameras, CCTV surveillance, high-bandwidth transmission - provide new and effective capabilities in the pursuit of criminals. Difficulties occur in the presentation of digital evidence in court in proving that no changes to such evidence have been made prior to its presentation.
Signum's VeriData technology provides a unique solution to the problem of data authentication, enabling in the case of digital images, subsequent modifications to be checked down to pixel level.
Where appropriate an enhanced version of VeriData can be used such that original images can be watermarked with relevant data - date/time, capture device, location, event, etc. - and authenticated.
VeriData therefore provides a powerful solution to ensure that evidential material is clearly identified and confirmed as original material.
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Epson are manufacturers of consumer level digital cameras and printers, amongst other things. They are using technologies that are no longer just the province of the spooks from the Ministry of Defence etc. and those at that sort of level. but has now got to the high street stores for amateur and business application. the ease of use makes it highly suitable for widespread law enforcement purposes. The company holds forth, thus: -
Given the advantages of speed, cost and convenience, digital imaging has
great potential for commercial use in applications once reserved for traditional
camera and film processing. Readily available image editing software programs
make manipulating digital images easy for the average PC user, increasing
the potential for their fraudulent use. As a consequence, the adoption of
digital imaging may be hindered in vertical market applications that require
image integrity (i.e., law enforcement, insurance, military, investigations,
quality assurance, etc.).
The EPSON Image Authentication System (lAS) addresses the need
for image integrity by providing image authentication from the point
of capture, in a standard file format. EPSON lAS-protected images
can be viewed with all commercially available software programs that
read JPEG images, so no additional proprietary image viewing
programs or systems are required. The verification program works
with Windows 95, Windows 98, and Windows NT operating
systems.
Operation is completely automatic. Simply load EPSON’s Image Authentication System software into the camera, then point and shoot. The software instantly embeds an invisible digital fingerprint within the image file. The image can then be verified as “untampered” using any PC equipped with the EPSON Image Authentication System.
Epson leaflet
on the system
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Video Enhancement is a term that describes a number of
different processes used to correct for poor lighting or
technique as well as some types of camera or recording equipment
failure. Never, in our application of Video Enhancement, is the
original recording damaged or altered in any way.
In most circumstances we will identify the significant degraded
area and then capture the best possible reproduction of that area
into the computer for enhancement purposes. Now begins the
application of various techniques to improve the captured image
of the captured image. Some of these techniques are quite
complex, some are as simple as contrast and brightness
adjustments.
When we start any enhancement task, it is absolutely imperative
that we start with the best possible image. This means the
original recording. We have all seen the photocopy of a photocopy
of a photocopy... that is barely readable. It is readable at all
because we are using the most sophisticated image processing
system known (our eyes, visual cortex and brain) and there are a
limited number of valid shapes to interpret (upper and lower case
letters and numbers). When we are dealing with an image, we do
not have the advantage of interpreting only "a limited
number of valid shapes". We become much more sensitive to
the degradation in the image caused by even a first generation
copy.
A first generation copy can put us so far behind the quality of
the original that we can waste a great deal of processing time
just to get back to the same level of clarity as the original. In
addition, each copy looses information and adds noise to the
image. This lost information is data that we can never have
available to us for processing and in cases of marginal images
can easily make the difference in identification or elimination
of a suspect in a processed image.
Incidentally, it is important to realize that the original
recording will be degraded by continuous replay. Note the
difference between your favorite brand new video and the same one
rented from your local video store. Replay of an important
section of video tape as few as 5 to 10 times can cause obvious,
permanent and unrecoverable loss of image quality.
Video Tape Authentication
Authentication of any type of recording is a verification that it
is a "Trustworthy" representation, in time, sequence
and content, of the event recorded. Even a simple press of the
"pause button" can be significant if it is determined
that a period of time long enough for the scene to be altered, in
meaning or content, has elapsed.
Video Tape Authentication requires the examination of the
original tape and recorder that made that tape. We have extended
the technique of using magnetic development, documented in the
Watergate examination, from audio to video recording. The
magnetic marks left by the recorder and frequently not part of
the visual image itself are examined to determine:
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If the recording is the original or a copy |
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Which buttons were depressed in the process of making that recording and where they are relative to the video images being presented |
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If part of the original recording was masked by recording over it at a later time |
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If the recorder presented is actually the one used to make the tape being evaluated |
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Which of a limited number of recorders was used to make a video recording |
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The answers to many other case specific questions |
If the original recorder is not available, we still may be able to determine
if more than one recorder was used to make the video tape, but the ability
to specify that a particular recorder was involved is lost.
While authentication of a copy is not possible, if this is the best evidence
or simply all that is available, some of the information about the making
of the original recording can survive the copying process. This may be enough
information to allow us to suggest that certain recording events probably
occurred. "
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An Appraisal of Technologies
of Political Control
European Parliament
Alan Lodge / Tash: ... tash@gn.apc.org