International Association for Cryptologic Research (IACR)
Abstract
Given a fixed-size block, cryptographic block functions gen-
erate outputs by a sequence of bitwise operations. Block functions are
widely used in the design of hash functions and stream ciphers. Their
correct implementations hence are crucial to computer security. We pro-
pose a method that leverages logic equivalence checking to verify assem-
bly implementations of cryptographic block functions. Logic equivalence
checking is a well-established technique from hardware verification. Using
our proposed method, we verify two dozen assembly implementations of
ChaCha20, SHA-256, and SHA-3 block functions from OpenSSL and
XKCP automatically. We also compare the performance of our technique
with the conventional SMT-based technique in experiments
