Cryptographic constant-time programming is an established coding discipline used in cryptography to secure programs against timing attacks. Most, if not all, cryptography library try to adhere to this coding style. The C programming language is oftentimes considered a portable assembly, and is hence used by a great number of cryptography libraries. However, what is executed by the hardware is actual assembly, not C. One can thus wonder whether security properties are preserved through compilation as even formally verified compilers only ensure preservation of observable behaviors.

We present in this paper how to derive a natural framework to prove preservation of cryptographic constant-time security from simulation based proofs of compiler correctness. We also give insights on how this could be adapted to CompCert.