The SKINNY family of tweakable block ciphers is intended for lightweight implementation in hardware and software, paper.
The algorithm author's web site provides a reference implementation in C, but it isn't terribly efficient - it is intended to be correct to make the algorithm easier to analyse. And that's OK.
This repository provides an alternative implementation in ISO C99 that is designed for efficient operation on 32-bit and 64-bit platforms. Alternative backends for CTR mode are also provided that can make use of GCC Vector Extensions or equivalent on systems that support 128-bit SIMD and 256-bit SIMD operations.
Other assembly language and SIMD speed-ups are definitely possible, such as this blindingly fast AVX2 implementation, and may be added later.
This implementation is designed to have constant-time and constant-cache behaviour. In particular, there are no lookup tables for the S-boxes.
Skinny-C is distributed under the terms of the MIT license.
For instructions on how to build and use Skinny-C, see the documentation.
For more information on this code, to report bugs, or to suggest improvements, please contact the author Rhys Weatherley via email.