oasisprotocol / deoxysii

deoxysii - Deoxys-II-256-128 for Go

This package provides a "from-the-paper" implementation of the Deoxys-II-256-128 v1.43 algorithm from the final CAESAR portfolio.

Implementations

• (ct32) Portable 32 bit constant time implementation (Extremely slow).

• (ct64) Portable 64 bit constant time implementation (Extremely slow).

• (aesni) SSSE3 + AESNI implementation for amd64

• (vartime) Portable and variable time (insecure) implementation, for illustrative purposes (tested/benchmarked but never reachable or usable by external consumers).

Notes

Performance for the AES-NI implementation still has room for improvement, however given that the Deoxys-BC-384 tweakable block cipher has 3 more rounds than AES-256, and Deoxys-II will do two passes over the data payload, it is likely reasonably close to what can be expected.

The pure software constant time implementation would benefit considerably from vector optimizations as the amount of internal paralleism is quite high, making it well suited to be implemented with bitslicing. Additionally a rather ludicrous amount of time is spent implementing the h permutation in software, that can be replaced with a single PSHUFB instruction.