06269163 is referenced by 232 patents and cites 16 patents.

A plaintext message to be encrypted is segmented into a number of words, e.g., four words stored in registers A, B, C and D, and an integer multiplication function is applied to a subset of the words, e.g., to the two words in registers B and D. The integer multiplication function may be a quadratic function of the form ƒ(x)=x(ax+b) or other suitable function such as a higher-order polynomial. The results of the integer multiplication function are rotated by lg w bits, where lg denotes log base

2

and w is the number of bits in a given word, to generate a pair of intermediate results t and u. An exclusive-or of another word, e.g., the word in register A, and one of the intermediate results, e.g., t, is rotated by an amount determined by the other intermediate result u. Similarly, an exclusive-or of the remaining word in register D and the intermediate result u is rotated by an amount determined by the other intermediate result t. An element of a secret key array is applied to each of these rotation results, and the register contents are then transposed. This process is repeated for a designated number of rounds to generate a ciphertext message. Pre-whitening and post-whitening operations may be included to ensure that the input or output does not reveal any internal information about any encryption round. Corresponding decryption operations may be used to decrypt the ciphertext message.

Title
Enhanced block ciphers with data-dependent rotations
Application Number
9/94649
Publication Number
6269163 (B1)
Application Date
June 15, 1998
Publication Date
July 31, 2001
Inventor
Yiqun Lisa Yin
San Mateo
CA, US
Raymond Mark Sidney
Foster City
CA, US
Matthew John Barton Robshaw
San Francisco
CA, US
Ronald L Rivest
Arlington
MA, US
Agent
Testa Hurwitz & Thibeault
US
Assignee
RSA Security
MA, US
IPC
H04K 1/00
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