int sycon_load(unsigned char *state, const unsigned char *npub, const unsigned char *k);
int sycon_ad(unsigned char *state, const unsigned char *ad, unsigned long long adlen);
int sycon_tag(unsigned char *tag, const unsigned char tlen, unsigned char *state, const unsigned char *k);

int crypto_aead_encrypt(
	unsigned char *c, unsigned long long *clen,
	const unsigned char *m, unsigned long long mlen,
	const unsigned char *ad, unsigned long long adlen,
	const unsigned char *nsec,
	const unsigned char *npub,
	const unsigned char *k
);

int crypto_aead_decrypt(
	unsigned char *m, unsigned long long *mlen,
	unsigned char *nsec,
	const unsigned char *c, unsigned long long clen,
	const unsigned char *ad, unsigned long long adlen,
	const unsigned char *npub,
	const unsigned char *k
);