On Wednesday, January 9, 2002, at 08:12 AM, Declan McCullagh wrote:
From: "MacGregor K. Phillips" <mkp@ns2.piol.net> To: "Top Secret Crypto Admin" <admin@topsecretcrypto.com> Subject: Top Secret Crypto Date: Wed, 9 Jan 2002 23:48:58 +0800 =========================================== Press Release by TAN$TAAFL Software Company =========================================== Contact Information: MacGregor K. Phillips President TAN$TAAFL Software Company 14 Foster St., Banicain Olongapo City, Philippines 2200
--familiar variants of the famed "virtual one time pad" elided---
Between the "can compress any file by 100:1" and the "virtual one time pads," it looks like OSEC (Organization of Snakeoil Exporting Countries) have struck snakeoil in many places. (In case anyone asks "How do you know virtual one time pads can't work?," a true one time pad a la Shannon uses shared sets of numbers which have no known algorithmic generator. If the pads can be generated from an algorithm, e.g., a seeded pseudorandom number generator, then an adversary could of course learn the algorithm and seed. With a true one time pad ("true" in the procedural sense, as no set of numbers can ever be proved to be random), any decryption is as good as any other. Meaning, the adversary can do no better than simply guessing at a solution. All of the bits in the message are XORed with bits determined by the procedural equivalent of a flip of a coin (maybe Johnson noise in a diode, maybe radioactive decay, maybe swings of a complex pendulum, maybe LSBs of a microphone listening to the wind, etc.). For Alice and Bob to share the often-large pads is of course the main limitation of one time pads. Military and diplomatic users can justify the housekeeping effort to share such pads. Even so, sometimes people start reusing pads, which means they are no longer "one time." And schemers think they can get the theoretical advantages of OTPs by generating the "virtual" OTP from an algorithm and a shared seed/key. Hence the production of snakeoil by OSEC. --Tim May --Tim May, Citizen-unit of of the once free United States " The tree of liberty must be refreshed from time to time with the blood of patriots & tyrants. "--Thomas Jefferson, 1787