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#include <assert.h>
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "crypto_core_hsalsa20.h"
#include "crypto_onetimeauth_poly1305.h"
#include "crypto_secretbox.h"
#include "crypto_stream_salsa20.h"
#include "utils.h"
static const unsigned char sigma[16] = {
'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', '2', '-', 'b', 'y', 't', 'e', ' ', 'k'
};
int
crypto_secretbox_detached(unsigned char *c, unsigned char *mac,
const unsigned char *m,
unsigned long long mlen, const unsigned char *n,
const unsigned char *k)
{
crypto_onetimeauth_poly1305_state state;
unsigned char block0[64U];
unsigned char subkey[crypto_stream_salsa20_KEYBYTES];
unsigned long long i;
unsigned long long mlen0;
crypto_core_hsalsa20(subkey, n, k, sigma);
if (((uintptr_t) c >= (uintptr_t) m &&
(uintptr_t) c - (uintptr_t) m < mlen) ||
((uintptr_t) m >= (uintptr_t) c &&
(uintptr_t) m - (uintptr_t) c < mlen)) {
memmove(c, m, mlen);
m = c;
}
memset(block0, 0U, crypto_secretbox_ZEROBYTES);
(void) sizeof(int[64U >= crypto_secretbox_ZEROBYTES ? 1 : -1]);
mlen0 = mlen;
if (mlen0 > 64U - crypto_secretbox_ZEROBYTES) {
mlen0 = 64U - crypto_secretbox_ZEROBYTES;
}
for (i = 0U; i < mlen0; i++) {
block0[i + crypto_secretbox_ZEROBYTES] = m[i];
}
crypto_stream_salsa20_xor(block0, block0,
mlen0 + crypto_secretbox_ZEROBYTES,
n + 16, subkey);
(void) sizeof(int[crypto_secretbox_ZEROBYTES >=
crypto_onetimeauth_poly1305_KEYBYTES ? 1 : -1]);
crypto_onetimeauth_poly1305_init(&state, block0);
memcpy(c, block0 + crypto_secretbox_ZEROBYTES, mlen0);
sodium_memzero(block0, sizeof block0);
if (mlen > mlen0) {
crypto_stream_salsa20_xor_ic(c + mlen0, m + mlen0, mlen - mlen0,
n + 16, 1U, subkey);
}
sodium_memzero(subkey, sizeof subkey);
crypto_onetimeauth_poly1305_update(&state, c, mlen);
crypto_onetimeauth_poly1305_final(&state, mac);
sodium_memzero(&state, sizeof state);
return 0;
}
int
crypto_secretbox_easy(unsigned char *c, const unsigned char *m,
unsigned long long mlen, const unsigned char *n,
const unsigned char *k)
{
if (mlen > SIZE_MAX - crypto_secretbox_MACBYTES) {
return -1;
}
return crypto_secretbox_detached(c + crypto_secretbox_MACBYTES,
c, m, mlen, n, k);
}
int
crypto_secretbox_open_detached(unsigned char *m, const unsigned char *c,
const unsigned char *mac,
unsigned long long clen,
const unsigned char *n,
const unsigned char *k)
{
unsigned char block0[64U];
unsigned char subkey[crypto_stream_salsa20_KEYBYTES];
unsigned long long i;
unsigned long long mlen0;
crypto_core_hsalsa20(subkey, n, k, sigma);
crypto_stream_salsa20(block0, crypto_stream_salsa20_KEYBYTES,
n + 16, subkey);
if (crypto_onetimeauth_poly1305_verify(mac, c, clen, block0) != 0) {
sodium_memzero(subkey, sizeof subkey);
return -1;
}
if (((uintptr_t) c >= (uintptr_t) m &&
(uintptr_t) c - (uintptr_t) m < clen) ||
((uintptr_t) m >= (uintptr_t) c &&
(uintptr_t) m - (uintptr_t) c < clen)) {
memmove(m, c, clen);
c = m;
}
mlen0 = clen;
if (mlen0 > 64U - crypto_secretbox_ZEROBYTES) {
mlen0 = 64U - crypto_secretbox_ZEROBYTES;
}
memcpy(block0 + crypto_secretbox_ZEROBYTES, c, mlen0);
crypto_stream_salsa20_xor(block0, block0,
crypto_secretbox_ZEROBYTES + mlen0,
n + 16, subkey);
for (i = 0U; i < mlen0; i++) {
m[i] = block0[i + crypto_secretbox_ZEROBYTES];
}
if (clen > mlen0) {
crypto_stream_salsa20_xor_ic(m + mlen0, c + mlen0, clen - mlen0,
n + 16, 1U, subkey);
}
sodium_memzero(subkey, sizeof subkey);
return 0;
}
int
crypto_secretbox_open_easy(unsigned char *m, const unsigned char *c,
unsigned long long clen, const unsigned char *n,
const unsigned char *k)
{
if (clen < crypto_secretbox_MACBYTES) {
return -1;
}
return crypto_secretbox_open_detached(m, c + crypto_secretbox_MACBYTES, c,
clen - crypto_secretbox_MACBYTES,
n, k);
}
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