Patent ID: 6578150
Filing Date: 2003-06-10
Classification: H04L

Abstract:
A data signal propagated over a propagation medium, said data signal including enciphered plaintext, said enciphered plaintext originating from plaintext which has been enciphered by enciphering said plaintext in a block cipher, said enciphering using a secret key, said enciphering comprising:processing round segments in a plurality of rounds of said block cipher, said plurality of rounds including a plurality of bit-moving rounds, each of said bit-moving rounds transforming input primary segments having a total of n bits of data into output primary segments having a total of n bits of data, each of said input primary segments originating directly or indirectly from said plaintext, each of said round segments of each said bit-moving round comprising a segment which originates from at least one of said input primary segments of said bit-moving round, each output primary segment of each said bit-moving round being equal to one of said round segments of said bit-moving round, said processing round segments in each of said bit-moving rounds comprising, predetermined bit-moving at least one present bit-value in a present bit-position of one of said round segments of said bit-moving round to determine a bit-value in an other bit-position of one of said round segments of said bit-moving round, said present bit-position being different than said other bit-position, variable bit-moving bits of one of said round segments of said bit-moving round by a number of bits dependent on a value from data of one of said round segments of said bit moving round, and wherein each of said segments is an ordered set of bits.