As PCs evolved the emphasis on backward compatibility and the need for user convenience (i.e. Hard drive technology existed long before the advent of personal computers (although the early personal computers started out with only cassette tape or diskette storage!). ![]() Since the structures of most of these media can be related to hard drives, a discussion of hard drive architecture will serve to illustrate the various data hiding mechanisms. Such abstractions create digital warrens where data may go unnoticed or, in some cases, be inaccessible.ĭigital storage encompasses a wide range of media including diskettes, hard drives, zip disks, USB flash drives, compact flash cards, CD ROMs, DVDs, etc. For efficiency considerations, addressability has to be at more abstract levels (typically words in primary, and blocks in secondary). If all storage were bit-addressable at the operating system level, there would be no place to hide data. The ability to hide data in computers is a byproduct of the system and peripheral architectures. Although this approach has not met with great success (and Camouflage is no longer supported) it is a great segue into the art of data hiding by taking advantage of the physical characteristics of computer systems. The disadvantage is that the hidden message is easily recovered with a hex-editor. This simple approach to data hiding has the advantage that the characteristics of the host or carrier message is unaffected, and are transparent to the host operating system and file managers. ![]() Camouflage embeds messages in the file slack (see below). The steganographic tool, Camouflage, was such a program (). For awhile they were even used for product licensing.Ī modern analogue might involve taking advantage of the physical characteristics of a storage medium to hide data. The upper 2 tracks were used to hide data by vendors and hackers alike. There was a difference between the number of tracks that a floppy drive controller could access (usually 81 or 82) and the number of tracks that were recognized by the operating system (DOS recognized only 80). One of the earliest examples of this arose when microcomputers were first introduced. within TCP/IP packet headers or Loki's use of the ICMP options field) or obscure or infrequently used addressable space in memory media. Obviously, these storage locations must be somewhat obscure or detection would be trivial. In this case, digital storage locations are used to hide or conceal data. However, there is also a physical aspect of digital data hiding. Overviews exist for cryptography, steganography, , and watermarking. Further, watermarking and steganography may be used with or without cryptography and imperceptible watermarking shares functionality with steganography, whereas perceptible watermarking does not. Cryptography and steganography share the feature that the object of interest is embedded, hidden or obscured, whereas the object of interest in watermarking is the host or carrier which is being protected by the object that is embedded, hidden or obscured. ![]() The steganographer, on the other hand is concerned with hiding the very communication of the message, while the digital watermarker attempts to add sufficient metadata to a message to establish ownership, provenance, source, etc. To illustrate, the cryptographer's interest is primarily with obscuring the content of a message, but not the communication of the message. Although related in the sense that they all are means to achieve secure or proprietary communications, there are differences among their three activities at a number of levels – some of which are quite subtle. In modern times, non-physical data hiding is usually associated with digital forms such as cryptography, steganography, and watermarking. Identity Theft and Financial Fraud Research and Operation Centerĭigital data hiding is actually a cluster-concept that spans many contexts. Hal Berghel, David Hoelzer, Michael Sthultz 74 (2008)ĭata Hiding Tactics for Windows and Unix File Systems Link to the Published Version in Advances in Computers, v. ![]() Data Hiding Tactics for Windows and Unix File Systems copyright notice
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