4 int encrypt(void *pt, int ptlen, void *key, int keylen, void *ct, int *ctlen);
5 int decrypt(void *ct, int ctlen, void *key, int keylen, void *pt, int *ptlen);
6 int hash(void *pt, int ptlen, void *tag, int *taglen);
7 int hmac(void *pt, int ptlen, void *key, int keylen, void *tag, int *taglen);