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From: Doug Hughes <Doug.Hughes@eng.auburn.edu> Date: Thu, 28 Sep 1995 19:31:00 -0500
A company in Israel named Elementrix has just announce at Interop an entirely new paradigm in secure transactions. They have a secure one time pad that allows people to exchange mail and ftp files back in forth in complete security without the worries of key management or storage or secure random number generation or synchronization.
As far as I could tell from your description, this is an autokey cipher -- not a OTP. An autokey cipher starts with a shared secret key and uses previous plaintext or ciphertext as part of the key. DES CBC is an autokey cipher. The original autokey used previous plaintext or ciphertext as the only key. More modern ones mix in the previous text. I had a design for one, several years ago, which kept a mapping in memory and changed the mapping based on incoming plaintext. Therefore, there is state information kept at both sides which keeps changing. One might think that if the attacker never gets in, today's randomness is just as good as yesterday's. That might even be true. However, there are many openings for finding relationships between yesterday's and today's ciphertexts. I look forward to seeing the actual algorithm. - Carl +--------------------------------------------------------------------------+ |Carl M. Ellison cme@tis.com http://www.clark.net/pub/cme | |Trusted Information Systems, Inc. http://www.tis.com/ | |3060 Washington Road PGP 2.6.2: 61E2DE7FCB9D7984E9C8048BA63221A2| |Glenwood MD 21738 Tel:(301)854-6889 FAX:(301)854-5363 | +--------------------------------------------------------------------------+ -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBMHBTU1QXJENzYr45AQHRigP/Yqw0T3n2SDubgRZIrKx8WpUSJtmBwcuf nIBxxwsOwu10sQti7hw3Zcj9tRM6JAcqFNh1U2LbYT3u7ELgh2Hicq0jLcr+3r4h B0H3LlbU9iv7WlETQF8Tw2KQcfDKLkYkeMRnS27cKnJIFHK9w0g4UTwabfB+m5SV sjnUZbv6Q1A= =P9X7 -----END PGP SIGNATURE-----