Frequently Asked Questions Frequently Asked Questions
Section 2 - SureSign Fingerprints
Section 3 - Fingerprint Detection
Section 4 - The SureSign Technology
Publishers, advertising agencies and other image users can avoid the risk of inadvertently infringing copyright by adopting the practice of applying one of the SureSign detection tools when they are uncertain about the origin or copyright status of an image file held by them. Large volume image users can automate the monitoring of images by using SureSign Server in its detect mode which generates a log file to provide data for export to an information management system.
When a fingerprint is detected, SureSign detector software displays (or logs) two codes: the unique registered user's code (Fingerprint ID) and the image identifier (Image ID). With this information the copyright owner may be identified, located and contacted so that usage rights and reproduction fees can be negotiated in advance of publication.
It is important to note that, whether or not a fingerprint is detected, image users are still under obligation to get the necessary approval from the copyright owner before using the image. One aim of SureSign is to make this an easier and more automated process.
At the moment, SureSign software allows a fingerprint to be embedded into rasterised image data, e.g. continuous tone bitmapped RGB or CMYK colour and greyscale images. In its current form, SureSign is not designed for ASCII-based electronic textural material or those vector file formats that are typically found in line-art, CAD and illustration applications. However, it is planned that future products will support an ever increasing range of digital data formats, and further extensions of the SureSign technology will protect digital video and digital audio material in a similar manner.
SureSign technology makes it possible to examine and thus determine the source of fingerprinted images that have been posted on web sites, or distributed on-line or by CD-ROMs. The format of the fingerprint is well suited to computerised monitoring using search engines and spiders and, thus, in the future, will allow content providers to automatically audit the use of their material. The resultant data could be used to facilitate automated billing. Signum Technologies expect to offer a web search service in the near future.
Section 2. SureSign Fingerprints
There are two main reasons why name and address information is not embedded into images:
The sophisticated structure of the fingerprint was specially designed to meet very stringent quality criteria regarding the reproducibility of the fingerprinted information and, in use, there is normally no discernible noise. Signum Technologies is familiar with the high quality standards imposed by reprographic use and, not surprisingly, the quality thresholds for SureSign are set at a particularly high level. The carefully structured SureSign fingerprint is also designed to not interfere with the screening used in common printing processes.
In general, yes, but since data compression techniques work by discarding varying degrees of image information and, if excessive levels of compression are used, the fingerprint could be difficult to detect in some circumstances. However, this usually only occurs at the point at which the data becomes unusable for quality reproduction anyway.
Tests have shown that a SureSign fingerprint can survive compression ratios of up to 30:1.
Not at all. Adding a SureSign fingerprint only modifies the values assigned to individual pixels, resulting in no difference between the volumes of the unfingerprinted source file and the fingerprinted one. Occasionally, users may experience a marginal file size increase when saving a fingerprinted image in a compressed file format such as JPEG (however, this is usually an insignificant amount).
No. It is impractical to try to remove a fingerprint from a file, since the considerable resources and time involved would, in most cases, be excessively disproportionate to the material's commercial value. Trying to create a 'pirate' program to remove the fingerprint from an image would be pointless, since each image has a totally unique fingerprint structure.
The permutation method used in SureSign is inherently secure and provides more options than are commonly utilised in either RSA or DES coding. Hacker programs that claim to remove a fingerprint, usually only render the underlying fingerprint data more difficult to read. Once an image is fingerprinted it is permanently changed and the fingerprint may still be recovered by 'forensic' means from images modified in this way.
Section 3. Fingerprint Detection
Detection is normally quick and simple, taking only seconds for average file sizes, but will vary according to the computer being used, the image size and whether a fingerprint is actually present or not. For example, a fingerprinted 5MB image file takes around 4 seconds to be processed by the SureSign Detector running within Adobe Photoshop on an Apple Macintosh Power Mac 8100. If there is no fingerprint present, the process takes about 16 seconds. The processing time is roughly proportional to image size (given that sufficient memory is allocated to the image editing application).
High volume users, such as publishers, can use the batch processing version of the software, SureSign Server, which runs unattended in the background, fingerprinting or detecting, optionally changing format, moving image files, and generating report logs with little or no impact on workflow.
Yes. It is possible to read fingerprints embedded in JPEG images published on web sites. It is also possible to read fingerprints embedded in Indexed Colour images (GIFs) although it is difficult to guarantee that the fingerprint can be detected in all circumstances, since this depends upon the size of sample data available and whether excessive image manipulation has taken place. Nonetheless, SureSign should prove to be of immense value to those who wish to monitor the use of their images on the Internet.
Generally, yes. SureSign fingerprints form part of the image data itself and, irrespective of the platform or operating system used, the SureSign fingerprints are retained when files are converted.
There are three general cases where a valid SureSign fingerprint may be outside the detection range of the detector tools:
(1) If the size of the image is too small, the detection tools may discover the presence of a fingerprint but be unable to fully decode the IDs. A warning is given in this case, however. The minimum image size to ensure successful detection is around 50KB although, in practice, a fingerprint may be detected in as little as 30KB of image data using the latest SureSign detection tools.
(2) If the image has been heavily manipulated by transformations such as distortion, rotation or re-sizing. Typically, in these cases, the fingerprint is still present in the data but may not be detectable. The detector is tolerant of a range of rotation and enlargement, but if the image has been manipulated outside this range, then it should be transformed back within range before the Detector will successfully recover the fingerprint. Signum Technologies is continuing to enhance the performance of the detection tools to cope with an ever-increasing range of transformations without the need for operator intervention to manipulate the image.
(3) If image data has been substantially degraded, either by severe re-touching, or by performing a conversion such as heavy compression or excessive down-sizing which results in image data being discarded. In this case, the fingerprint itself may be degraded to the extent that it can no longer be fully decoded or even detected. Generally speaking, if 10% or more of the original data remains, then a SureSign fingerprint should be readable.
Signum Technologies has carefully designed the core algorithm to allow future enhancement of detection tools without having to alter the basic structure of the fingerprint. Therefore, we anticipate that the Detector will become increasingly sophisticated, and more sensitive.
Yes. It is possible to detect the fingerprint in scanned-in halftone printed material and other print media such as thermal dye sublimation prints in colour and monochrome. However, it is difficult to guarantee that the fingerprint can be detected in all circumstances because of the widely varying screen types, printing processes and materials used in print production. Having said that, this useful additional function can allow a great many users to monitor usage of their image material in print.
Generally speaking, the higher the quality of the print and the larger the print sample, the easier it is to detect a fingerprint in hard copy.
Section 4. The SureSign Technology
Yes. SureSign technology is very suitable for use in a wide range of photographic, video, audio and multimedia applications in diverse sectors such as digital and print publishing, entertainment, packaging, security, healthcare, cartography and electronic commerce.
Signum has ensured that its fingerprinting technologycan be easily integrated into all kinds of application and system software and can also be incorporated into the firmware of the growing range of hardware devices such as digital still and video cameras, for example.
For these purposes, Signum Technologies offers a special SureSign Software Development Kit (SDK) for application developers who wish to integrate SureSign fingerprinting functions into their applications, systems or hardware. Public and private-key versions of the SDK are available as standard for copyright communication and protection, and data validation applications . UNIX (Solaris), Mac OS and Windows95/NT operating systems are supported but Signum Technologies can provide customised versions for use with other operating systems.
Whilst these are all security devices for digital material and the terms are frequently used interchangeably, they are nevertheless three distinctly different protection methods.
Encryption works by locking an object file with a 'key' and providing that key only to authorised users. Whilst this generally provides a high degree of active security, once an encrypted file is opened, the contents become unprotected and may then be readily edited, copied and disseminated without any further form of control.
Watermarking usually places a visible mark on a still or video image. Watermarks can, of course, be removed by image processing applications and, for this reason, do not offer any high degree of protection. They are, however, frequently used as a promotional tool for identifying low resolution view files (of limited commercial value) when used as part of a 'sampler' or catalogue.
Fingerprinting, also known as hidden watermarking or digital steganography, protects image data at a very deep level with fingerprint data interwoven into the image data itself. Unlike visible watermarking or encryption, a fingerprint is designed to remain in place even after the file has been opened (or unlocked), edited or copied. The fingerprint structure was devised to be robust and not to be visible either in print or on screen in normal use, making it a highly effective tool in both copyright protection and data validation applications.
In copyright protection applications, fingerprinting and encryption are entirely complementary techniques and, used in combination, offer a sophisticated level of both active and passive protection.
Yes. Similar products are planned to support digital video and digital audio applications in the future. In both these cases, the fingerprint information will still be kept to a minimum but, since these types of data are more tolerant of introduced 'noise', more or larger identifying fields may be incorporated into the fingerprint. This should permit the support of emerging industry standard identifying codes, such as Isrc, DOI, etc.
Yes. Signum Technologies have a number of patent applications relating to fingerprinting:
1. Security codes for digital images
Patent application: 9400971.9 Date of filing: 19th January 1994
In the name of MOR Limited (subsequently changed to Signum Technologies Limited)
2. The Fingerprint technique
Patent application: 9504221.2 Date of filing: 2nd March 1995
In the name of MOR Limited (subsequently changed to Signum Technologies Limited)
3. Data Integrity
Patent application: 9513790.7 Date of filing: 3rd July 1995
In the name of HighWater Designs Limited (subsequently changed to Signum Technologies Limited)
If you are concerned about the copyright protection of your digital images, joining the Registry is an important first step.
When you join you will be issued with a unique identifier which establishes you as the copyright owner of your images. This identifier is invisibly embedded into your images using our fingerprint writer software - anyone finding this identifier (using our detector software) will be able to trace you as the owner of the image by searching the Registry on our web site.
You can also mark photographic equipment, processed film and other personal possessions with your Fingerprint ID.
The price for one year's membership in the Registry will depend upon whether you are an individual or corporate user. Individual users of the SureSign Plug-ins currently pay 39 pounds sterling/60 US Dollars per year. Corporate users should contact Signum Technologies for details.
When you join the Registry you get the following:
Access to the Registry is available:
Data Record - A file, or part of a file, containing digital information.
Noise - Low-level random data within a digital signal.
Object - Visual or audio information in digital form.
Object data - Information contained within a data record. May be a continuous tone still image, a digital video or sound clip.
Threshold of perception - The point at which the fingerprint information starts to be perceived by human eye or ear.
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