/* Do modular exponentiation using floating point multiply code. */
mp_err mp_exptmod_f(const mp_int * montBase,
const mp_int * exponent,
const mp_int * modulus,
mp_int * result,
mp_mont_modulus *mmm,
int nLen,
mp_size bits_in_exponent,
mp_size window_bits,
mp_size odd_ints)
{
mp_digit *mResult;
double *dBuf = 0, *dm1, *dn, *dSqr, *d16Tmp, *dTmp;
double dn0;
mp_size i;
mp_err res;
int expOff;
int dSize = 0, oddPowSize, dTmpSize;
mp_int accum1;
double *oddPowers[MAX_ODD_INTS];
/* function for computing n0prime only works if n0 is odd */
MP_DIGITS(&accum1) = 0;
for (i = 0; i < MAX_ODD_INTS; ++i)
oddPowers[i] = 0;
MP_CHECKOK( mp_init_size(&accum1, 3 * nLen + 2) );
mp_set(&accum1, 1);
MP_CHECKOK( s_mp_to_mont(&accum1, mmm, &accum1) );
MP_CHECKOK( s_mp_pad(&accum1, nLen) );
oddPowSize = 2 * nLen + 1;
dTmpSize = 2 * oddPowSize;
dSize = sizeof(double) * (nLen * 4 + 1 +
((odd_ints + 1) * oddPowSize) + dTmpSize);
dBuf = (double *)malloc(dSize);
dm1 = dBuf; /* array of d32 */
dn = dBuf + nLen; /* array of d32 */
dSqr = dn + nLen; /* array of d32 */
d16Tmp = dSqr + nLen; /* array of d16 */
dTmp = d16Tmp + oddPowSize;
for (i = 0; i < odd_ints; ++i) {
oddPowers[i] = dTmp;
dTmp += oddPowSize;
}
mResult = (mp_digit *)(dTmp + dTmpSize); /* size is nLen + 1 */
/* Make dn and dn0 */
conv_i32_to_d32(dn, MP_DIGITS(modulus), nLen);
dn0 = (double)(mmm->n0prime & 0xffff);
/* Make dSqr */
conv_i32_to_d32_and_d16(dm1, oddPowers[0], MP_DIGITS(montBase), nLen);
mont_mulf_noconv(mResult, dm1, oddPowers[0],
dTmp, dn, MP_DIGITS(modulus), nLen, dn0);
conv_i32_to_d32(dSqr, mResult, nLen);
for (i = 1; i < odd_ints; ++i) {
mont_mulf_noconv(mResult, dSqr, oddPowers[i - 1],
dTmp, dn, MP_DIGITS(modulus), nLen, dn0);
conv_i32_to_d16(oddPowers[i], mResult, nLen);
}
s_mp_copy(MP_DIGITS(&accum1), mResult, nLen); /* from, to, len */
for (expOff = bits_in_exponent - window_bits; expOff >= 0; expOff -= window_bits) {
mp_size smallExp;
MP_CHECKOK( mpl_get_bits(exponent, expOff, window_bits) );
smallExp = (mp_size)res;
if (window_bits == 1) {
if (!smallExp) {
SQR;
} else if (smallExp & 1) {
SQR; MUL(0);
} else {
ABORT;
}
} else if (window_bits == 4) {
if (!smallExp) {
SQR; SQR; SQR; SQR;
} else if (smallExp & 1) {
SQR; SQR; SQR; SQR; MUL(smallExp/2);
} else if (smallExp & 2) {
SQR; SQR; SQR; MUL(smallExp/4); SQR;
} else if (smallExp & 4) {
SQR; SQR; MUL(smallExp/8); SQR; SQR;
} else if (smallExp & 8) {
SQR; MUL(smallExp/16); SQR; SQR; SQR;
} else {
ABORT;
}
} else if (window_bits == 5) {
if (!smallExp) {
SQR; SQR; SQR; SQR; SQR;
} else if (smallExp & 1) {
SQR; SQR; SQR; SQR; SQR; MUL(smallExp/2);
} else if (smallExp & 2) {
SQR; SQR; SQR; SQR; MUL(smallExp/4); SQR;
} else if (smallExp & 4) {
SQR; SQR; SQR; MUL(smallExp/8); SQR; SQR;
} else if (smallExp & 8) {
SQR; SQR; MUL(smallExp/16); SQR; SQR; SQR;
} else if (smallExp & 0x10) {
SQR; MUL(smallExp/32); SQR; SQR; SQR; SQR;
} else {
ABORT;
}
} else if (window_bits == 6) {
if (!smallExp) {
SQR; SQR; SQR; SQR; SQR; SQR;
} else if (smallExp & 1) {
SQR; SQR; SQR; SQR; SQR; SQR; MUL(smallExp/2);
} else if (smallExp & 2) {
SQR; SQR; SQR; SQR; SQR; MUL(smallExp/4); SQR;
} else if (smallExp & 4) {
SQR; SQR; SQR; SQR; MUL(smallExp/8); SQR; SQR;
} else if (smallExp & 8) {
SQR; SQR; SQR; MUL(smallExp/16); SQR; SQR; SQR;
} else if (smallExp & 0x10) {
SQR; SQR; MUL(smallExp/32); SQR; SQR; SQR; SQR;
} else if (smallExp & 0x20) {
SQR; MUL(smallExp/64); SQR; SQR; SQR; SQR; SQR;
} else {
ABORT;
}
} else {
ABORT;
}
}
s_mp_copy(mResult, MP_DIGITS(&accum1), nLen); /* from, to, len */
res = s_mp_redc(&accum1, mmm);
mp_exch(&accum1, result);
CLEANUP:
mp_clear(&accum1);
if (dBuf) {
if (dSize)
memset(dBuf, 0, dSize);
free(dBuf);
}
return res;
}
/* Do modular exponentiation using integer multiply code. */
mp_err mp_exptmod_i(const mp_int * montBase,
const mp_int * exponent,
const mp_int * modulus,
mp_int * result,
mp_mont_modulus *mmm,
int nLen,
mp_size bits_in_exponent,
mp_size window_bits,
mp_size odd_ints)
{
mp_int *pa1, *pa2, *ptmp;
mp_size i;
mp_err res;
int expOff;
mp_int accum1, accum2, power2, oddPowers[MAX_ODD_INTS];
/* power2 = base ** 2; oddPowers[i] = base ** (2*i + 1); */
/* oddPowers[i] = base ** (2*i + 1); */
MP_DIGITS(&accum1) = 0;
MP_DIGITS(&accum2) = 0;
MP_DIGITS(&power2) = 0;
for (i = 0; i < MAX_ODD_INTS; ++i) {
MP_DIGITS(oddPowers + i) = 0;
}
MP_CHECKOK( mp_init_size(&accum1, 3 * nLen + 2) );
MP_CHECKOK( mp_init_size(&accum2, 3 * nLen + 2) );
MP_CHECKOK( mp_init_copy(&oddPowers[0], montBase) );
mp_init_size(&power2, nLen + 2 * MP_USED(montBase) + 2);
MP_CHECKOK( mp_sqr(montBase, &power2) ); /* power2 = montBase ** 2 */
MP_CHECKOK( s_mp_redc(&power2, mmm) );
for (i = 1; i < odd_ints; ++i) {
mp_init_size(oddPowers + i, nLen + 2 * MP_USED(&power2) + 2);
MP_CHECKOK( mp_mul(oddPowers + (i - 1), &power2, oddPowers + i) );
MP_CHECKOK( s_mp_redc(oddPowers + i, mmm) );
}
/* set accumulator to montgomery residue of 1 */
mp_set(&accum1, 1);
MP_CHECKOK( s_mp_to_mont(&accum1, mmm, &accum1) );
pa1 = &accum1;
pa2 = &accum2;
for (expOff = bits_in_exponent - window_bits; expOff >= 0; expOff -= window_bits) {
mp_size smallExp;
MP_CHECKOK( mpl_get_bits(exponent, expOff, window_bits) );
smallExp = (mp_size)res;
if (window_bits == 1) {
if (!smallExp) {
SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 1) {
SQR(pa1,pa2); MUL(0,pa2,pa1);
} else {
ABORT;
}
} else if (window_bits == 4) {
if (!smallExp) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
} else if (smallExp & 1) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
MUL(smallExp/2, pa1,pa2); SWAPPA;
} else if (smallExp & 2) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2);
MUL(smallExp/4,pa2,pa1); SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 4) {
SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/8,pa1,pa2);
SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 8) {
SQR(pa1,pa2); MUL(smallExp/16,pa2,pa1); SQR(pa1,pa2);
SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
} else {
ABORT;
}
} else if (window_bits == 5) {
if (!smallExp) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 1) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
SQR(pa1,pa2); MUL(smallExp/2,pa2,pa1);
} else if (smallExp & 2) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
MUL(smallExp/4,pa1,pa2); SQR(pa2,pa1);
} else if (smallExp & 4) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2);
MUL(smallExp/8,pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
} else if (smallExp & 8) {
SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/16,pa1,pa2);
SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
} else if (smallExp & 0x10) {
SQR(pa1,pa2); MUL(smallExp/32,pa2,pa1); SQR(pa1,pa2);
SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
} else {
ABORT;
}
} else if (window_bits == 6) {
if (!smallExp) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
SQR(pa1,pa2); SQR(pa2,pa1);
} else if (smallExp & 1) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/2,pa1,pa2); SWAPPA;
} else if (smallExp & 2) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
SQR(pa1,pa2); MUL(smallExp/4,pa2,pa1); SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 4) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
MUL(smallExp/8,pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 8) {
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2);
MUL(smallExp/16,pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 0x10) {
SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/32,pa1,pa2);
SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 0x20) {
SQR(pa1,pa2); MUL(smallExp/64,pa2,pa1); SQR(pa1,pa2);
SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
} else {
ABORT;
}
} else {
ABORT;
}
}
res = s_mp_redc(pa1, mmm);
mp_exch(pa1, result);
CLEANUP:
mp_clear(&accum1);
mp_clear(&accum2);
mp_clear(&power2);
for (i = 0; i < odd_ints; ++i) {
mp_clear(oddPowers + i);
}
return res;
}
/* Do modular exponentiation using integer multiply code. */
mp_err mp_exptmod_safe_i(const mp_int * montBase,
const mp_int * exponent,
const mp_int * modulus,
mp_int * result,
mp_mont_modulus *mmm,
int nLen,
mp_size bits_in_exponent,
mp_size window_bits,
mp_size num_powers)
{
mp_int *pa1, *pa2, *ptmp;
mp_size i;
mp_size first_window;
mp_err res;
int expOff;
mp_int accum1, accum2, accum[WEAVE_WORD_SIZE];
mp_int tmp;
unsigned char *powersArray;
unsigned char *powers;
MP_DIGITS(&accum1) = 0;
MP_DIGITS(&accum2) = 0;
MP_DIGITS(&accum[0]) = 0;
MP_DIGITS(&accum[1]) = 0;
MP_DIGITS(&accum[2]) = 0;
MP_DIGITS(&accum[3]) = 0;
MP_DIGITS(&tmp) = 0;
powersArray = (unsigned char *)malloc(num_powers*(nLen*sizeof(mp_digit)+1));
if (powersArray == NULL) {
res = MP_MEM;
goto CLEANUP;
}
/* powers[i] = base ** (i); */
powers = (unsigned char *)MP_ALIGN(powersArray,num_powers);
/* grab the first window value. This allows us to preload accumulator1
* and save a conversion, some squares and a multiple*/
MP_CHECKOK( mpl_get_bits(exponent,
bits_in_exponent-window_bits, window_bits) );
first_window = (mp_size)res;
MP_CHECKOK( mp_init_size(&accum1, 3 * nLen + 2) );
MP_CHECKOK( mp_init_size(&accum2, 3 * nLen + 2) );
MP_CHECKOK( mp_init_size(&tmp, 3 * nLen + 2) );
/* build the first WEAVE_WORD powers inline */
/* if WEAVE_WORD_SIZE is not 4, this code will have to change */
if (num_powers > 2) {
MP_CHECKOK( mp_init_size(&accum[0], 3 * nLen + 2) );
MP_CHECKOK( mp_init_size(&accum[1], 3 * nLen + 2) );
MP_CHECKOK( mp_init_size(&accum[2], 3 * nLen + 2) );
MP_CHECKOK( mp_init_size(&accum[3], 3 * nLen + 2) );
mp_set(&accum[0], 1);
MP_CHECKOK( s_mp_to_mont(&accum[0], mmm, &accum[0]) );
MP_CHECKOK( mp_copy(montBase, &accum[1]) );
SQR(montBase, &accum[2]);
MUL_NOWEAVE(montBase, &accum[2], &accum[3]);
MP_CHECKOK( mpi_to_weave(accum, powers, nLen, num_powers) );
if (first_window < 4) {
MP_CHECKOK( mp_copy(&accum[first_window], &accum1) );
first_window = num_powers;
}
} else {
if (first_window == 0) {
mp_set(&accum1, 1);
MP_CHECKOK( s_mp_to_mont(&accum1, mmm, &accum1) );
} else {
/* assert first_window == 1? */
MP_CHECKOK( mp_copy(montBase, &accum1) );
}
}
/*
* calculate all the powers in the powers array.
* this adds 2**(k-1)-2 square operations over just calculating the
* odd powers where k is the window size in the two other mp_modexpt
* implementations in this file. We will get some of that
* back by not needing the first 'k' squares and one multiply for the
* first window */
for (i = WEAVE_WORD_SIZE; i < num_powers; i++) {
int acc_index = i & (WEAVE_WORD_SIZE-1); /* i % WEAVE_WORD_SIZE */
if ( i & 1 ) {
MUL_NOWEAVE(montBase, &accum[acc_index-1] , &accum[acc_index]);
/* we've filled the array do our 'per array' processing */
if (acc_index == (WEAVE_WORD_SIZE-1)) {
MP_CHECKOK( mpi_to_weave(accum, powers + i - (WEAVE_WORD_SIZE-1),
nLen, num_powers) );
if (first_window <= i) {
MP_CHECKOK( mp_copy(&accum[first_window & (WEAVE_WORD_SIZE-1)],
&accum1) );
first_window = num_powers;
}
}
} else {
/* up to 8 we can find 2^i-1 in the accum array, but at 8 we our source
* and target are the same so we need to copy.. After that, the
* value is overwritten, so we need to fetch it from the stored
* weave array */
if (i > 2* WEAVE_WORD_SIZE) {
MP_CHECKOK(weave_to_mpi(&accum2, powers+i/2, nLen, num_powers));
SQR(&accum2, &accum[acc_index]);
} else {
int half_power_index = (i/2) & (WEAVE_WORD_SIZE-1);
if (half_power_index == acc_index) {
/* copy is cheaper than weave_to_mpi */
MP_CHECKOK(mp_copy(&accum[half_power_index], &accum2));
SQR(&accum2,&accum[acc_index]);
} else {
SQR(&accum[half_power_index],&accum[acc_index]);
}
}
}
}
/* if the accum1 isn't set, Then there is something wrong with our logic
* above and is an internal programming error.
*/
#if MP_ARGCHK == 2
assert(MP_USED(&accum1) != 0);
#endif
/* set accumulator to montgomery residue of 1 */
pa1 = &accum1;
pa2 = &accum2;
for (expOff = bits_in_exponent - window_bits*2; expOff >= 0; expOff -= window_bits) {
mp_size smallExp;
MP_CHECKOK( mpl_get_bits(exponent, expOff, window_bits) );
smallExp = (mp_size)res;
/* handle unroll the loops */
switch (window_bits) {
case 1:
if (!smallExp) {
SQR(pa1,pa2); SWAPPA;
} else if (smallExp & 1) {
SQR(pa1,pa2); MUL_NOWEAVE(montBase,pa2,pa1);
} else {
abort();
}
break;
case 6:
SQR(pa1,pa2); SQR(pa2,pa1);
/* fall through */
case 4:
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
MUL(smallExp, pa1,pa2); SWAPPA;
break;
case 5:
SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
SQR(pa1,pa2); MUL(smallExp,pa2,pa1);
break;
default:
abort(); /* could do a loop? */
}
}
res = s_mp_redc(pa1, mmm);
mp_exch(pa1, result);
CLEANUP:
mp_clear(&accum1);
mp_clear(&accum2);
mp_clear(&accum[0]);
mp_clear(&accum[1]);
mp_clear(&accum[2]);
mp_clear(&accum[3]);
mp_clear(&tmp);
/* PORT_Memset(powers,0,num_powers*nLen*sizeof(mp_digit)); */
free(powersArray);
return res;
}