Towards Side-Channel Resistant Block Cipher Usage or Can We Encrypt Without Side-Channel Countermeasures?

Based on re-keying techniques by Abdalla, Bellare, and Borst [1, 2], we consider two black-box secure block cipher based symmetric encryption schemes, which we prove secure in the physically observable cryptography model. They are proven side-channel secure against a strong type of adversary that can adaptively choose the leakage function as long as the leaked information is bounded. It turns out that our simple construction is side-channel secure against all types of attacks that satisfy some reasonable assumptions. In particular, the security turns out to be negligible in the block cipher’s block size n, for all attacks. We also show that our ideas result in an interesting alternative to the implementation of block ciphers using different logic styles or masking countermeasures.