A sha256 implementation in C
Check for gcc
gcc --version
or for clang
clang --version
Setup for linux/wsl
sudo apt update
sudo apt install build-essential
sudo apt-get install manpages-dev (optional)
make
Setup for windows
Download mingw-get-setup.exe at https://sourceforge.net/projects/mingw/files/Installer/mingw-get-setup.exe/download
Run the exe and follow installation steps
make windows
Setup for mac
Download developer tools via Apple's Xcode or Apple's website at https://developer.apple.com/develop/
make
Write #include "sha256.h" or #include "path/to/sha256.h" (depending on how you are using it)
The include at the top of sha256.c should also be adjusted accordingly to your use case.
However, if sha256.c and sha256.h are in the same directory, the include in sha256.c doesn't need to be modified.
The Message Digest (output) is printed out in hexadecimal. To verify that my sha256 implementation works, I created some simple tests.
Run make tests or make tets_windows accordingly to use sha256.c
Run python tests.py or python3 tests.py accordingly to use Python's hashlib.
Run python -V or python3 -V to check if you have python installed
sha256() can be compiled into a .so, but only on UNIX machines.
Use make so for linux/WSL or make so_mac for mac.
Load .so with CDLL() from ctypes as seen in so.py
Run with python2, python3 is not supported yet.
Any lines with find . -type f -exec touch {} + can be removed (from the makefile)
Variables at the top of the makefile can be adjusted to your preferences
Legacy just holds previous versions of my sha256 code
This implementation uses C without any external libraries. Only little_endian() came from outside sources.
In terms of optimizations, I use -O3 when compiling (sometimes -O2), __restrict/restrict when possible, and inlining the small functions. I am currently looking into removing branches in the code and using various bit hacks to make things go faster.
I have not tested any of these programs on a mac
For posix_sha256.c only:
posix_sha256.c relies on a POSIX function getdelim() that is not accessible on windows machines, even with #define _GNU_SOURCE.
There are various indentation anomalies, but many of them are hard to get rid (tabs and spaces on my editor and github).
Use sha256.c at your own risk, I created this function and may not be completely safe.