MD5 Hashing

A simple MD5 hashing implementation. Usage:

unsigned char digest[MD5_SIZE];
md5_context ctx;
md5_init(&ctx);
{
    md5_update(&ctx, src, sz);
}
md5_finalize(&ctx, digest);

The above code is the literal implementation of md5() which is a high level helper for hashing data of a known size:

unsigned char hash[MD5_SIZE];
md5(hash, data, dataSize);

Use md5_format() to format the digest as a hex string. The capacity of the output buffer needs to be at least MD5_SIZE_FORMATTED bytes.

This library does not perform any memory allocations and does not use anything from the standard library except for size_t and NULL, both of which are drawn in from stddef.h. No other standard headers are included.

There is no need to link to anything with this library. You can use MD5_IMPLEMENTATION to define the implementation section, or you can use md5.c if you prefer a traditional header/source pair.