memcpy(cipher->key, key + len - cipher->keylen, cipher->keylen + cipher->blklen);
memcpy(cipher->key + cipher->keylen, key + len - cipher->keylen - cipher->blklen, cipher->blklen);
memcpy(cipher->key, key + len - cipher->keylen, cipher->keylen + cipher->blklen);
memcpy(cipher->key + cipher->keylen, key + len - cipher->keylen - cipher->blklen, cipher->blklen);