// The input encrypted as though 128bit counter mode is being used. The extra
// state information to record how much of the 128bit block we have used is
// contained in *num, and the encrypted counter is kept in ecount_buf. Both
// *num and ecount_buf must be initialised with zeros before the first call to
// CRYPTO_ctr128_encrypt().
//
// This algorithm assumes that the counter is in the x lower bits of the IV
// (ivec), and that the application has full control over overflow and the rest
// of the IV. This implementation takes NO responsibility for checking that
// the counter doesn't overflow into the rest of the IV when incremented.
void CRYPTO_ctr128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
const void *key, uint8_t ivec[16],
uint8_t ecount_buf[16], unsigned int *num,
block128_f block) {
unsigned int n;
assert(key && ecount_buf && num);
assert(len == 0 || (in && out));
assert(*num < 16);
n = *num;
while (n && len) {
*(out++) = *(in++) ^ ecount_buf[n];
--len;
n = (n + 1) % 16;
}
#if STRICT_ALIGNMENT
if (((uintptr_t)in | (uintptr_t)out |
(uintptr_t)ecount_buf) % sizeof(size_t) != 0) {
size_t l = 0;
while (l < len) {
if (n == 0) {
(*block)(ivec, ecount_buf, key);
ctr128_inc(ivec);
}
out[l] = in[l] ^ ecount_buf[n];
++l;
n = (n + 1) % 16;
}
*num = n;
return;
}
#endif
while (len >= 16) {
(*block)(ivec, ecount_buf, key);
ctr128_inc(ivec);
for (n = 0; n < 16; n += sizeof(size_t)) {
store_word_le(out + n,
load_word_le(in + n) ^ load_word_le(ecount_buf + n));
}
len -= 16;
out += 16;
in += 16;
n = 0;
}
if (len) {
(*block)(ivec, ecount_buf, key);
ctr128_inc(ivec);
while (len--) {
out[n] = in[n] ^ ecount_buf[n];
++n;
}
}
*num = n;
}
/* The input encrypted as though 128bit counter mode is being used. The extra
* state information to record how much of the 128bit block we have used is
* contained in *num, and the encrypted counter is kept in ecount_buf. Both
* *num and ecount_buf must be initialised with zeros before the first call to
* CRYPTO_ctr128_encrypt().
*
* This algorithm assumes that the counter is in the x lower bits of the IV
* (ivec), and that the application has full control over overflow and the rest
* of the IV. This implementation takes NO responsibility for checking that
* the counter doesn't overflow into the rest of the IV when incremented. */
void CRYPTO_ctr128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
const void *key, uint8_t ivec[16],
uint8_t ecount_buf[16], unsigned int *num,
block128_f block) {
unsigned int n;
size_t l=0;
assert(in && out && key && ecount_buf && num);
assert(*num < 16);
assert((16 % sizeof(size_t)) == 0);
n = *num;
while (n && len) {
*(out++) = *(in++) ^ ecount_buf[n];
--len;
n = (n + 1) % 16;
}
if (STRICT_ALIGNMENT &&
((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
while (l < len) {
if (n == 0) {
(*block)(ivec, ecount_buf, key);
ctr128_inc(ivec);
}
out[l] = in[l] ^ ecount_buf[n];
++l;
n = (n + 1) % 16;
}
*num = n;
return;
}
while (len >= 16) {
(*block)(ivec, ecount_buf, key);
ctr128_inc(ivec);
for (; n < 16; n += sizeof(size_t))
*(size_t *)(out + n) = *(size_t *)(in + n) ^ *(size_t *)(ecount_buf + n);
len -= 16;
out += 16;
in += 16;
n = 0;
}
if (len) {
(*block)(ivec, ecount_buf, key);
ctr128_inc(ivec);
while (len--) {
out[n] = in[n] ^ ecount_buf[n];
++n;
}
}
*num = n;
}
static void ctr128_inc_aligned(unsigned char *counter)
{
size_t *data, c, d, n;
const union {
long one;
char little;
} is_endian = {
1
};
if (is_endian.little || ((size_t)counter % sizeof(size_t)) != 0) {
ctr128_inc(counter);
return;
}
data = (size_t *)counter;
c = 1;
n = 16 / sizeof(size_t);
do {
--n;
d = data[n] += c;
/* did addition carry? */
c = ((d - c) & ~d) >> (sizeof(size_t) * 8 - 1);
} while (n);
}
static void ctr128_inc_aligned(unsigned char *counter)
{
size_t *data, c, n;
const union {
long one;
char little;
} is_endian = {
1
};
if (is_endian.little) {
ctr128_inc(counter);
return;
}
data = (size_t *)counter;
n = 16 / sizeof(size_t);
do {
--n;
c = data[n];
++c;
data[n] = c;
if (c)
return;
} while (n);
}
static void
ctr128_inc_aligned(unsigned char *counter)
{
size_t *data,c,n;
if (_BYTE_ORDER == _LITTLE_ENDIAN) {
ctr128_inc(counter);
return;
}
data = (size_t *)counter;
n = 16/sizeof(size_t);
do {
--n;
c = data[n];
++c;
data[n] = c;
if (c) return;
} while (n);
}
/*
* The input encrypted as though 128bit counter mode is being used. The
* extra state information to record how much of the 128bit block we have
* used is contained in *num, and the encrypted counter is kept in
* ecount_buf. Both *num and ecount_buf must be initialised with zeros
* before the first call to CRYPTO_ctr128_encrypt(). This algorithm assumes
* that the counter is in the x lower bits of the IV (ivec), and that the
* application has full control over overflow and the rest of the IV. This
* implementation takes NO responsability for checking that the counter
* doesn't overflow into the rest of the IV when incremented.
*/
void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
size_t len, const void *key,
unsigned char ivec[16],
unsigned char ecount_buf[16], unsigned int *num,
block128_f block)
{
unsigned int n;
size_t l = 0;
assert(in && out && key && ecount_buf && num);
assert(*num < 16);
n = *num;
#if !defined(OPENSSL_SMALL_FOOTPRINT)
if (16 % sizeof(size_t) == 0) { /* always true actually */
do {
while (n && len) {
*(out++) = *(in++) ^ ecount_buf[n];
--len;
n = (n + 1) % 16;
}
# if defined(STRICT_ALIGNMENT)
if (((size_t)in | (size_t)out | (size_t)ecount_buf)
% sizeof(size_t) != 0)
break;
# endif
while (len >= 16) {
(*block) (ivec, ecount_buf, key);
ctr128_inc_aligned(ivec);
for (n = 0; n < 16; n += sizeof(size_t))
*(size_t *)(out + n) =
*(size_t *)(in + n) ^ *(size_t *)(ecount_buf + n);
len -= 16;
out += 16;
in += 16;
n = 0;
}
if (len) {
(*block) (ivec, ecount_buf, key);
ctr128_inc_aligned(ivec);
while (len--) {
out[n] = in[n] ^ ecount_buf[n];
++n;
}
}
*num = n;
return;
} while (0);
}
/* the rest would be commonly eliminated by x86* compiler */
#endif
while (l < len) {
if (n == 0) {
(*block) (ivec, ecount_buf, key);
ctr128_inc(ivec);
}
out[l] = in[l] ^ ecount_buf[n];
++l;
n = (n + 1) % 16;
}
*num = n;
}
