const char* websocket_derive_key(const char* key){
static char hex[512] = {0,};
static char magic[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
/* compute concaternated hash */
sha1_t sha = sha1_new();
sha1_update(sha, key, strlen(key));
sha1_update(sha, magic, strlen(magic));
/* encode hash as base64 */
base64encode(sha1_hash_bytes(sha), 20, hex, sizeof(hex));
sha1_free(sha);
return hex;
}
/*
* SHA-1 HMAC context setup
*/
void sha1_hmac_starts( sha1_context *ctx, const unsigned char *key,
size_t keylen )
{
if( keylen > 64 ) // Key shortened if greater than BLOCK SIZE (64 bytes)
{
sha1_context cty;
sha1_init(&cty);
sha1_starts(&cty);
sha1_update(&cty, key, keylen); // Get the 20 char digest of the key
sha1_finish(&cty, ctx->key); // Store the digest in ctx.key
sha1_free(&cty);
ctx->keyLen = 20;
}
else {
ctx->keyLen = keylen; // Use the key as is
memcpy(ctx->key, key, keylen); // Store the key in ctx.key
}
}
static void sha1_ctx_free( void *ctx )
{
sha1_free( (sha1_context *) ctx );
polarssl_free( ctx );
}
