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Encryption Modes with Almost Free Message Integrity

2008; Springer Science+Business Media; Volume: 21; Issue: 4 Linguagem: Inglês

10.1007/s00145-008-9024-z

1432-1378

Charanjit S. Jutla,

Cryptography and Data Security

We define a new mode of operation for block ciphers which, in addition to providing confidentiality, also ensures message integrity. In contrast, previously for message integrity a separate pass was required to compute a cryptographic message authentication code (MAC). The new mode of operation, called Integrity Aware Parallelizable Mode (IAPM), requires a total of m+1 block cipher evaluations on a plain-text of length m blocks. For comparison, the well-known CBC (cipher block chaining) encryption mode requires m block cipher evaluations, and the second pass of computing the CBC-MAC essentially requires additional m+1 block cipher evaluations. As the name suggests, the new mode is also highly parallelizable.