This is an implementation of the SHA-256 secure hash algorithm defined in FIPS 180-4
It is not a byte-oriented implementation. Still, it may complement a portable byte-oriented C version of AES-256 at www.literatecode.com/aes256
This implementation supports clang (recommended) and GCC C compilers.
Other compilers may also work with some minor code tweaking. Apologies for
not caring about the seamless support of the MSVC compiler any longer.
Check the legacy section below if you still need that.
Use make or sh sha256.c -c -o sha256.o to compile into an object file
that you may link with your project later.
Use make test or sh sha256.c -DSHA256_SELF_TEST__ to compile an
executable binary that will perform a few known answer tests for SHA-256.
We rely on C Bounded Model Checker to formally verify code properties.
Use make verify to verify the self-testing code.
If you want to focus verification on a single function, use
make verify FUNC=XYZ, where XYZ is a function name.
Check https://github.com/diffblue/cbmc for the latest version of CBMC.
- 2010: The original code was written.
- 2013: The original code was published on GitHub.
- 2014: The Mark 2 version was written (cleaner, closer to a reference implementation, formally verifiable).
- 2017: The Mark 2 version was added to the repository.
- 2022: The revamped Mark 2 version superseded the original code.
The original version is still available under the tag legacy and provided only for reference. Therefore, it is no longer supported or recommended.