int skein_init(struct skein_ctx *ctx, size_t hash_bit_len)
{
int ret = SKEIN_FAIL;
size_t x_len = 0;
u64 *x = NULL;
u64 tree_info = SKEIN_CFG_TREE_INFO_SEQUENTIAL;
skein_assert_ret(ctx, SKEIN_FAIL);
/*
* The following two lines rely of the fact that the real Skein
* contexts are a union in out context and thus have tha maximum
* memory available. The beauty of C :-) .
*/
x = ctx->m.s256.x;
x_len = ctx->skein_size / 8;
/*
* If size is the same and hash bit length is zero then reuse
* the save chaining variables.
*/
switch (ctx->skein_size) {
case SKEIN_256:
ret = skein_256_init_ext(&ctx->m.s256, hash_bit_len,
tree_info, NULL, 0);
break;
case SKEIN_512:
ret = skein_512_init_ext(&ctx->m.s512, hash_bit_len,
tree_info, NULL, 0);
break;
case SKEIN_1024:
ret = skein_1024_init_ext(&ctx->m.s1024, hash_bit_len,
tree_info, NULL, 0);
break;
}
if (ret == SKEIN_SUCCESS) {
/*
* Save chaining variables for this combination of size and
* hash_bit_len
*/
memcpy(ctx->x_save, x, x_len);
}
return ret;
}
int skein_mac_init(struct skein_ctx *ctx, const u8 *key, size_t key_len,
size_t hash_bit_len)
{
int ret = SKEIN_FAIL;
u64 *x = NULL;
size_t x_len = 0;
u64 tree_info = SKEIN_CFG_TREE_INFO_SEQUENTIAL;
skein_assert_ret(ctx, SKEIN_FAIL);
x = ctx->m.s256.x;
x_len = ctx->skein_size/8;
skein_assert_ret(hash_bit_len, SKEIN_BAD_HASHLEN);
switch (ctx->skein_size) {
case SKEIN_256:
ret = skein_256_init_ext(&ctx->m.s256, hash_bit_len,
tree_info,
(const u8 *)key, key_len);
break;
case SKEIN_512:
ret = skein_512_init_ext(&ctx->m.s512, hash_bit_len,
tree_info,
(const u8 *)key, key_len);
break;
case SKEIN_1024:
ret = skein_1024_init_ext(&ctx->m.s1024, hash_bit_len,
tree_info,
(const u8 *)key, key_len);
break;
}
if (ret == SKEIN_SUCCESS) {
/*
* Save chaining variables for this combination of key,
* key_len, hash_bit_len
*/
memcpy(ctx->x_save, x, x_len);
}
return ret;
}