#include "os.h"#include <libsec.h> static voidccpolyotk(Chachastate *cs, DigestState *ds){	uchar otk[ChachaBsize]; 	memset(ds, 0, sizeof(*ds));	memset(otk, 0, 32);	chacha_setblock(cs, 0);	chacha_encrypt(otk, ChachaBsize, cs);	poly1305(nil, 0, otk, 32, nil, ds);} static voidccpolypad(uchar *buf, ulong nbuf, DigestState *ds){	static uchar zeros[16] = {0};	ulong npad; 	if(nbuf == 0)		return;	poly1305(buf, nbuf, nil, 0, nil, ds);	npad = nbuf % 16;	if(npad == 0)		return;	poly1305(zeros, 16 - npad, nil, 0, nil, ds);} static voidccpolylen(ulong n, uchar tag[16], DigestState *ds){	uchar info[8]; 	info[0] = n;	info[1] = n>>8;	info[2] = n>>16;	info[3] = n>>24;	info[4] = 0;	info[5] = 0;	info[6] = 0;	info[7] = 0;	poly1305(info, 8, nil, 0, tag, ds);} voidccpoly_encrypt(uchar *dat, ulong ndat, uchar *aad, ulong naad, uchar tag[16], Chachastate *cs){	DigestState ds; 	ccpolyotk(cs, &ds);	if(cs->ivwords == 2){		poly1305(aad, naad, nil, 0, nil, &ds);		ccpolylen(naad, nil, &ds);		chacha_encrypt(dat, ndat, cs);		poly1305(dat, ndat, nil, 0, nil, &ds);		ccpolylen(ndat, tag, &ds);	} else {		ccpolypad(aad, naad, &ds);		chacha_encrypt(dat, ndat, cs);		ccpolypad(dat, ndat, &ds);		ccpolylen(naad, nil, &ds);		ccpolylen(ndat, tag, &ds);	}} intccpoly_decrypt(uchar *dat, ulong ndat, uchar *aad, ulong naad, uchar tag[16], Chachastate *cs){	DigestState ds;	uchar tmp[16]; 	ccpolyotk(cs, &ds);	if(cs->ivwords == 2){		poly1305(aad, naad, nil, 0, nil, &ds);		ccpolylen(naad, nil, &ds);		poly1305(dat, ndat, nil, 0, nil, &ds);		ccpolylen(ndat, tmp, &ds);	} else {		ccpolypad(aad, naad, &ds);		ccpolypad(dat, ndat, &ds);		ccpolylen(naad, nil, &ds);		ccpolylen(ndat, tmp, &ds);	}	if(tsmemcmp(tag, tmp, 16) != 0)		return -1;	chacha_encrypt(dat, ndat, cs);	return 0;}