Triple DES Cipher Block Chaining with Output Feedback Masking

We propose a new mode of multiple encryption, namely Triple DES cipher block chaining with output feedback masking. The aim is to provide strong protection against certain attacks (dictionary attacks and matching ciphertext attacks) which exploit the DES blocksize of 64 bits. The new mode obtains this protection through the introduction of secret masking values that are Exclusive-ORed with the intermediate outputs of each triple-DES encryption operation. The secret mask value is derived from a fourth encryption operation per message block, in addition to the three used in previous modes. The new mode is part of a suite of encryption modes proposed in the ANSI X9.F.1 Triple-DES draft standard (X9.52).

By: Don Coppersmith, Don B. Johnson (Certicom) and Stephen M. Matyas (IBM Cryptography Center, Poughkeepsie_

Published in: RC20591 in 1996


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