PolyE+CTR: A Swiss-Army-Knife Mode for Block Ciphers

摘要

In this paper, we propose a new kind of mode of operation for block ciphers. By a single key, such a mode can protect data for privacy, authenticity and they both respectively, so we call it Swiss-Army-Knife mode. The purpose of SAK mode is to increase diversity of security services for a single key, thus we can provide different protections for data with different security requirements, without rekeying the underlying block cipher. As an example, we propose PolyE+CTR, an SAK mode that combines an authentication mode PolyE and a nonce-based encryption mode CTR in the authentication-and-encryption method. PolyE+CTR is provably secure with high efficiency.