int (*update_fn)(PPP_CIPHER_CTX *ctx, unsigned char *out, int *outl, const unsigned char *in, int inl);
int (*final_fn)(PPP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
void (*clean_fn)(PPP_CIPHER_CTX *ctx);
int (*update_fn)(PPP_CIPHER_CTX *ctx, unsigned char *out, int *outl, const unsigned char *in, int inl);
int (*final_fn)(PPP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
void (*clean_fn)(PPP_CIPHER_CTX *ctx);