WjCryptLib

WjCryptLib is a public-domain collection of cryptographic primitives in C: MD5, SHA-1, SHA-256, SHA-512, RC4, AES, and AES in CBC, CTR and OFB modes. Each module is independent — a single .c file and matching .h file are usually all that's needed.

The code is portable across little-endian and big-endian architectures, builds on macOS, Linux and Windows, and supports OpenMP for parallel AES-CTR.

Placed into Public Domain by WaterJuice 2013 – 2026.

Algorithms

To use a single algorithm, copy the files listed below into your project.

Algorithm	Files
MD5	WjCryptLib_Md5.{h,c}
SHA-1	WjCryptLib_Sha1.{h,c}
SHA-256	WjCryptLib_Sha256.{h,c}
SHA-512	WjCryptLib_Sha512.{h,c}
RC4	WjCryptLib_Rc4.{h,c}
AES	WjCryptLib_Aes.{h,c}
AES-CBC	WjCryptLib_AesCbc.{h,c} (plus AES)
AES-CTR	WjCryptLib_AesCtr.{h,c} (plus AES)
AES-OFB	WjCryptLib_AesOfb.{h,c} (plus AES)

Algorithm choice

MD5, SHA-1 and RC4 are included for interoperability with existing systems but are considered cryptographically broken and should not be used for new work. Prefer SHA-256 or SHA-512 over MD5 and SHA-1, and prefer an AES mode over RC4.

Building

The canonical build setup is CMakeLists.txt. CMake generates build files for any system — Visual Studio projects on Windows, Unix Makefiles or Ninja on Linux/macOS, Xcode, and so on. Install CMake from https://cmake.org/download/.

cmake -S . -B build
cmake --build build

A thin Makefile wrapper is provided as a convenience that delegates everything to CMake. It works on macOS, Linux, and Windows native when GNU Make is installed:

make build      # configure and build everything
make test       # build then run the test harness via ctest
make clean      # remove the build tree
make help       # show available targets (default)

Test and demo programs

In the projects/ directory there are several programs that compile to command-line executables:

• WjCryptLibTest — Verifies every algorithm against known test vectors. Useful when porting to a new platform.
• Md5String, Sha1String, Sha256String, Sha512String — Compute a hash of a string given on the command line.
• Rc4Output — Output an RC4 stream as hex.
• AesBlock — Encrypt or decrypt a single AES block.
• AesCtrOutput, AesOfbOutput — Output an AES-CTR or AES-OFB stream as hex.

Changelog

See ChangeLog.md for the full version history.

License

This software is released into the public domain. See UNLICENSE for the full text, or refer to http://unlicense.org/.