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#include <stdint.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include "core.h"
#include "crypto_aead_chacha20poly1305.h"
#include "crypto_aead_xchacha20poly1305.h"
#include "crypto_core_hchacha20.h"
#include "crypto_onetimeauth_poly1305.h"
#include "crypto_stream_chacha20.h"
#include "crypto_verify_16.h"
#include "randombytes.h"
#include "utils.h"
#include "private/chacha20_ietf_ext.h"
#include "private/common.h"
static const unsigned char _pad0[16] = { 0 };
static int
_encrypt_detached(unsigned char *c,
unsigned char *mac,
unsigned long long *maclen_p,
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)
{
crypto_onetimeauth_poly1305_state state;
unsigned char block0[64U];
unsigned char slen[8U];
(void) nsec;
crypto_stream_chacha20_ietf_ext(block0, sizeof block0, npub, k);
crypto_onetimeauth_poly1305_init(&state, block0);
sodium_memzero(block0, sizeof block0);
crypto_onetimeauth_poly1305_update(&state, ad, adlen);
crypto_onetimeauth_poly1305_update(&state, _pad0, (0x10 - adlen) & 0xf);
crypto_stream_chacha20_ietf_ext_xor_ic(c, m, mlen, npub, 1U, k);
crypto_onetimeauth_poly1305_update(&state, c, mlen);
crypto_onetimeauth_poly1305_update(&state, _pad0, (0x10 - mlen) & 0xf);
STORE64_LE(slen, (uint64_t) adlen);
crypto_onetimeauth_poly1305_update(&state, slen, sizeof slen);
STORE64_LE(slen, (uint64_t) mlen);
crypto_onetimeauth_poly1305_update(&state, slen, sizeof slen);
crypto_onetimeauth_poly1305_final(&state, mac);
sodium_memzero(&state, sizeof state);
if (maclen_p != NULL) {
*maclen_p = crypto_aead_chacha20poly1305_ietf_ABYTES;
}
return 0;
}
static int
_decrypt_detached(unsigned char *m,
unsigned char *nsec,
const unsigned char *c,
unsigned long long clen,
const unsigned char *mac,
const unsigned char *ad,
unsigned long long adlen,
const unsigned char *npub,
const unsigned char *k)
{
crypto_onetimeauth_poly1305_state state;
unsigned char block0[64U];
unsigned char slen[8U];
unsigned char computed_mac[crypto_aead_chacha20poly1305_ietf_ABYTES];
unsigned long long mlen;
int ret;
(void) nsec;
crypto_stream_chacha20_ietf_ext(block0, sizeof block0, npub, k);
crypto_onetimeauth_poly1305_init(&state, block0);
sodium_memzero(block0, sizeof block0);
crypto_onetimeauth_poly1305_update(&state, ad, adlen);
crypto_onetimeauth_poly1305_update(&state, _pad0, (0x10 - adlen) & 0xf);
mlen = clen;
crypto_onetimeauth_poly1305_update(&state, c, mlen);
crypto_onetimeauth_poly1305_update(&state, _pad0, (0x10 - mlen) & 0xf);
STORE64_LE(slen, (uint64_t) adlen);
crypto_onetimeauth_poly1305_update(&state, slen, sizeof slen);
STORE64_LE(slen, (uint64_t) mlen);
crypto_onetimeauth_poly1305_update(&state, slen, sizeof slen);
crypto_onetimeauth_poly1305_final(&state, computed_mac);
sodium_memzero(&state, sizeof state);
COMPILER_ASSERT(sizeof computed_mac == 16U);
ret = crypto_verify_16(computed_mac, mac);
sodium_memzero(computed_mac, sizeof computed_mac);
if (m == NULL) {
return ret;
}
if (ret != 0) {
memset(m, 0, mlen);
return -1;
}
crypto_stream_chacha20_ietf_ext_xor_ic(m, c, mlen, npub, 1U, k);
return 0;
}
int
crypto_aead_xchacha20poly1305_ietf_encrypt_detached(unsigned char *c,
unsigned char *mac,
unsigned long long *maclen_p,
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)
{
unsigned char k2[crypto_core_hchacha20_OUTPUTBYTES];
unsigned char npub2[crypto_aead_chacha20poly1305_ietf_NPUBBYTES] = { 0 };
int ret;
crypto_core_hchacha20(k2, npub, k, NULL);
memcpy(npub2 + 4, npub + crypto_core_hchacha20_INPUTBYTES,
crypto_aead_chacha20poly1305_ietf_NPUBBYTES - 4);
ret = _encrypt_detached(c, mac, maclen_p, m, mlen, ad, adlen,
nsec, npub2, k2);
sodium_memzero(k2, crypto_core_hchacha20_OUTPUTBYTES);
return ret;
}
int
crypto_aead_xchacha20poly1305_ietf_encrypt(unsigned char *c,
unsigned long long *clen_p,
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)
{
unsigned long long clen = 0ULL;
int ret;
if (mlen > crypto_aead_xchacha20poly1305_ietf_MESSAGEBYTES_MAX) {
sodium_misuse();
}
ret = crypto_aead_xchacha20poly1305_ietf_encrypt_detached
(c, c + mlen, NULL, m, mlen, ad, adlen, nsec, npub, k);
if (clen_p != NULL) {
if (ret == 0) {
clen = mlen + crypto_aead_xchacha20poly1305_ietf_ABYTES;
}
*clen_p = clen;
}
return ret;
}
int
crypto_aead_xchacha20poly1305_ietf_decrypt_detached(unsigned char *m,
unsigned char *nsec,
const unsigned char *c,
unsigned long long clen,
const unsigned char *mac,
const unsigned char *ad,
unsigned long long adlen,
const unsigned char *npub,
const unsigned char *k)
{
unsigned char k2[crypto_core_hchacha20_OUTPUTBYTES];
unsigned char npub2[crypto_aead_chacha20poly1305_ietf_NPUBBYTES] = { 0 };
int ret;
crypto_core_hchacha20(k2, npub, k, NULL);
memcpy(npub2 + 4, npub + crypto_core_hchacha20_INPUTBYTES,
crypto_aead_chacha20poly1305_ietf_NPUBBYTES - 4);
ret = _decrypt_detached(m, nsec, c, clen, mac, ad, adlen, npub2, k2);
sodium_memzero(k2, crypto_core_hchacha20_OUTPUTBYTES);
return ret;
}
int
crypto_aead_xchacha20poly1305_ietf_decrypt(unsigned char *m,
unsigned long long *mlen_p,
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)
{
unsigned long long mlen = 0ULL;
int ret = -1;
if (clen >= crypto_aead_xchacha20poly1305_ietf_ABYTES) {
ret = crypto_aead_xchacha20poly1305_ietf_decrypt_detached
(m, nsec,
c, clen - crypto_aead_xchacha20poly1305_ietf_ABYTES,
c + clen - crypto_aead_xchacha20poly1305_ietf_ABYTES,
ad, adlen, npub, k);
}
if (mlen_p != NULL) {
if (ret == 0) {
mlen = clen - crypto_aead_xchacha20poly1305_ietf_ABYTES;
}
*mlen_p = mlen;
}
return ret;
}
size_t
crypto_aead_xchacha20poly1305_ietf_keybytes(void)
{
return crypto_aead_xchacha20poly1305_ietf_KEYBYTES;
}
size_t
crypto_aead_xchacha20poly1305_ietf_npubbytes(void)
{
return crypto_aead_xchacha20poly1305_ietf_NPUBBYTES;
}
size_t
crypto_aead_xchacha20poly1305_ietf_nsecbytes(void)
{
return crypto_aead_xchacha20poly1305_ietf_NSECBYTES;
}
size_t
crypto_aead_xchacha20poly1305_ietf_abytes(void)
{
return crypto_aead_xchacha20poly1305_ietf_ABYTES;
}
size_t
crypto_aead_xchacha20poly1305_ietf_messagebytes_max(void)
{
return crypto_aead_xchacha20poly1305_ietf_MESSAGEBYTES_MAX;
}
void
crypto_aead_xchacha20poly1305_ietf_keygen(unsigned char k[crypto_aead_xchacha20poly1305_ietf_KEYBYTES])
{
randombytes_buf(k, crypto_aead_xchacha20poly1305_ietf_KEYBYTES);
}
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