A simple SHA-1 hashing implementation. Usage:
unsigned char digest[SHA1_SIZE];
sha1_context ctx;
sha1_init(&ctx);
{
sha1_update(&ctx, src, sz);
}
sha1_finalize(&ctx, digest);
The above code is the literal implementation of sha1() which is a high level helper for hashing
data of a known size:
unsigned char hash[SHA1_SIZE];
sha1(hash, data, dataSize);
Use sha1_format() to format the digest as a hex string. The capacity of the output buffer needs to
be at least SHA1_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 SHA1_IMPLEMENTATION to define the implementation section, or you can use sha1.c if you prefer a traditional header/source pair.
This implements both methods defined in RFC 3174. Method 1 will be used by default. If you want to
use Method 2, define SHA1_USE_RFC_METHOD_2 at compile time.
#define SHA1_USE_RFC_METHOD_2
#define SHA1_IMPLEMENTATION
#include "sha1.h"
No effort has been made to optimize this beyond the algorithms described in RGC 3174. If you're looking for the fastest SHA-1 implementation you'll need to look elsewhere. An optimized implementation may come later.