source: lib/sha1.c @ 34afea7

#include "sha1.h"
#include <string.h>
#include <stdio.h>


void sha1_init(sha1_state_t *ctx)
{
        *ctx = g_checksum_new(G_CHECKSUM_SHA1);
}

void sha1_append(sha1_state_t *ctx, const guint8 * message_array, guint len)
{
        g_checksum_update(*ctx, message_array, len);
}

void sha1_finish(sha1_state_t *ctx, guint8 digest[SHA1_HASH_SIZE])
{
        gsize digest_len = SHA1_HASH_SIZE;
        g_checksum_get_digest(*ctx, digest, &digest_len);
        g_checksum_free(*ctx);
}

#define HMAC_BLOCK_SIZE 64

/* BitlBee addition: */
void sha1_hmac(const char *key_, size_t key_len, const char *payload, size_t payload_len, guint8 digest[SHA1_HASH_SIZE])
{
        sha1_state_t sha1;
        guint8 hash[SHA1_HASH_SIZE];
        guint8 key[HMAC_BLOCK_SIZE+1];
        int i;
        
        if( key_len == 0 )
                key_len = strlen( key_ );
        if( payload_len == 0 )
                payload_len = strlen( payload );
        
        /* Create K. If our current key is >64 chars we have to hash it,
           otherwise just pad. */
        memset( key, 0, HMAC_BLOCK_SIZE + 1 );
        if( key_len > HMAC_BLOCK_SIZE )
        {
                sha1_init( &sha1 );
                sha1_append( &sha1, (guint8*) key_, key_len );
                sha1_finish( &sha1, key );
        }
        else
        {
                memcpy( key, key_, key_len );
        }
        
        /* Inner part: H(K XOR 0x36, text) */
        sha1_init( &sha1 );
        for( i = 0; i < HMAC_BLOCK_SIZE; i ++ )
                key[i] ^= 0x36;
        sha1_append( &sha1, key, HMAC_BLOCK_SIZE );
        sha1_append( &sha1, (const guint8*) payload, payload_len );
        sha1_finish( &sha1, hash );
        
        /* Final result: H(K XOR 0x5C, inner stuff) */
        sha1_init( &sha1 );
        for( i = 0; i < HMAC_BLOCK_SIZE; i ++ )
                key[i] ^= 0x36 ^ 0x5c;
        sha1_append( &sha1, key, HMAC_BLOCK_SIZE );
        sha1_append( &sha1, hash, SHA1_HASH_SIZE );
        sha1_finish( &sha1, digest );
}

/* I think this follows the scheme described on:
   http://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_.28random.29
   My random data comes from a SHA1 generator but hey, it's random enough for
   me, and RFC 4122 looks way more complicated than I need this to be.
   
   Returns a value that must be free()d. */
char *sha1_random_uuid( sha1_state_t * context )
{
        guint8 dig[SHA1_HASH_SIZE];
        char *ret = g_new0( char, 40 ); /* 36 chars + \0 */
        int i, p;
        
        sha1_finish(context, dig);
        for( p = i = 0; i < 16; i ++ )
        {
                if( i == 4 || i == 6 || i == 8 || i == 10 )
                        ret[p++] = '-';
                if( i == 6 )
                        dig[i] = ( dig[i] & 0x0f ) | 0x40;
                if( i == 8 )
                        dig[i] = ( dig[i] & 0x30 ) | 0x80;
                
                sprintf( ret + p, "%02x", dig[i] );
                p += 2;
        }
        ret[p] = '\0';
        
        return ret;
}