## Cryptology ePrint Archive: Report 2006/188

New Blockcipher Modes of Operation with Beyond the Birthday Bound Security

Tetsu Iwata

Abstract: In this paper, we define and analyze a new blockcipher mode of operation for encryption, CENC, which stands for Cipher-based ENCryption. CENC has the following advantages: (1) beyond the birthday bound security, (2) security proofs with the standard PRP assumption, (3) highly efficient, (4) single blockcipher key, (5) fully parallelizable, (6) allows precomputation of keystream, and (7) allows random access. CENC is based on the new construction of from PRPs to PRF conversion,'' which is of independent interest. Based on CENC and a universal hash-based MAC (Wegman-Carter MAC), we also define a new authenticated-encryption with associated-data scheme, CHM, which stands for CENC with Hash-based MAC. The security of CHM is also beyond the birthday bound.

Category / Keywords: secret-key cryptography / blockcipher, modes of operation, security proofs, birthday bound

Publication Info: Appeared at FSE 2006. This is the full version.