Fast Decryption: a New Feature of Misuse-Resistant AE

Abstract

Misuse-resistant AE (MRAE) is a class of authenticated encryption (AE) that has a resistance against a potential misuse (repeat) of nonce. MRAE has received significant attention from the initial proposal by Rogaway and Shrimpton. They showed a generic MRAE construction called SIV. SIV becomes a de-facto scheme for MRAE, however, one notable drawback is its two-pass operation for both encryption and decryption. This implies that MRAE built on SIV is slower than the integrated nonce-based AE schemes, such as OCB. In this paper, we propose a new method to improve this situation. Particularly, our MRAE proposal (decryption-fast SIV or DFV) allows to decrypt as fast as a plain decryption, hence theoretically doubles its speed from the original SIV, while keeping the encryption speed equivalent to SIV. We present several generic compositions for DFV and their instantiations.

Keywords

• Authenticated Encryption
• Nonce Misuse
• MRAE
• Decryption
• SIV
• OCB