NAME

mhash - Hash Library

VERSION

mhash 0.5.0

SYNOPSIS

 #include "mhash.h"

 Informative Functions 

 size_t   mhash_count(void);
 size_t   mhash_get_block_size(hashid type);
 char    *mhash_get_hash_name(hashid type);

 Initializing Functions 

 MHASH    mhash_init(hashid type);

 Update Functions 

 int      mhash(MHASH thread, const void *plaintext, size_t size);

 Finalizing Functions 

 void    *mhash_end(MHASH thread);

 Available Hashes 

 enum hashid {
        CRC32,
        MD5,
        SHA1,
        HAVAL,
        RIPEMD160,
        RIPEMD128,
        SNEFRU,
        TIGER,
        GOST,
        CRC32B
 };

 typedef enum hashid hashid;

DESCRIPTION

The mhash library provides an easy to use C interface for several hash algorithms (also known as ``one-way'' algorithm). These can be used to create checksums, message digests and more. Currently, MD5, SHA1, GOST, TIGER, RIPE-MD160, HAVAL and several other algorithms are supported.

API FUNCTIONS

We will describe the API of mhash in detail now. The order follows the one in the SYNOPSIS directly.

size_t mhash_count(void);

This returns the hashid of the last available hash. Hashes are numbered from 0 to mhash_count().

size_t mhash_get_block_size(hashid type);

If type exists, this returns the used blocksize of the hash type in bytes. Otherwise, it returns 0.

char *mhash_get_hash_name(hashid type);

If type exists, this returns the name of the hash type. Otherwise, a NULL pointer is returned. The string is allocated with malloc(3) seperately, so do not forget to free(3) it.

MHASH mhash_init(hashid type);

This setups a context to begin hashing using the algorithm type. It returns a descriptor to that context which will result in leaking memory, if you do not call mhash_end(3) later. Returns MHASH_FAILED on failure.

int mhash(MHASH thread, const void *plaintext, size_t size);

This updates the context described by thread with plaintext. size is the length of plaintext which may be binary data.

void *mhash_end(MHASH thread);

This frees all resources associated with thread and returns the result of the whole hashing operation (the ``digest'').

EXAMPLE

Hashing STDIN until EOF.

 #include <stdio.h>
 #include <stdlib.h>
 #include "mhash.h"

 int main(void) {
        int i;
        MHASH td;
        unsigned char buffer;
        unsigned char *hash;

        td = mhash_init(MD5);

        if(td == MHASH_FAILED) exit(1);

        while(fread(&buffer, 1, 1, stdin) == 1) {
                mhash(td, &buffer, 1);
        }

        hash = mhash_end(td);

        printf ("Hash:");
        for (i = 0; i < mhash_get_block_size(MD5); i++) {
                printf ("%.2x", hash[i]);
        }
        printf ("\n");

        exit(0);
 }

HISTORY

This library was originally written by Nikos Mavroyanopoulos <nmav@hellur.gr> who passed the project over to Sascha Schumann <ss@2ns.de> in May 1999.

BUGS

If you find any, please send a bug report (preferrably together with a patch) to the maintainer ss@2ns.de with a detailed description on how to reproduce the bug.

AUTHOR

Sascha Schumann <ss@2ns.de>