diff options
Diffstat (limited to 'security/nss/lib/freebl/ecl/ecp_256.c')
| -rw-r--r-- | security/nss/lib/freebl/ecl/ecp_256.c | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/ecl/ecp_256.c b/security/nss/lib/freebl/ecl/ecp_256.c new file mode 100644 index 000000000..ad4e630c1 --- /dev/null +++ b/security/nss/lib/freebl/ecl/ecp_256.c @@ -0,0 +1,401 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "ecp.h" +#include "mpi.h" +#include "mplogic.h" +#include "mpi-priv.h" + +/* Fast modular reduction for p256 = 2^256 - 2^224 + 2^192+ 2^96 - 1. a can be r. + * Uses algorithm 2.29 from Hankerson, Menezes, Vanstone. Guide to + * Elliptic Curve Cryptography. */ +static mp_err +ec_GFp_nistp256_mod(const mp_int *a, mp_int *r, const GFMethod *meth) +{ + mp_err res = MP_OKAY; + mp_size a_used = MP_USED(a); + int a_bits = mpl_significant_bits(a); + mp_digit carry; + +#ifdef ECL_THIRTY_TWO_BIT + mp_digit a8 = 0, a9 = 0, a10 = 0, a11 = 0, a12 = 0, a13 = 0, a14 = 0, a15 = 0; + mp_digit r0, r1, r2, r3, r4, r5, r6, r7; + int r8; /* must be a signed value ! */ +#else + mp_digit a4 = 0, a5 = 0, a6 = 0, a7 = 0; + mp_digit a4h, a4l, a5h, a5l, a6h, a6l, a7h, a7l; + mp_digit r0, r1, r2, r3; + int r4; /* must be a signed value ! */ +#endif + /* for polynomials larger than twice the field size + * use regular reduction */ + if (a_bits < 256) { + if (a == r) + return MP_OKAY; + return mp_copy(a, r); + } + if (a_bits > 512) { + MP_CHECKOK(mp_mod(a, &meth->irr, r)); + } else { + +#ifdef ECL_THIRTY_TWO_BIT + switch (a_used) { + case 16: + a15 = MP_DIGIT(a, 15); + case 15: + a14 = MP_DIGIT(a, 14); + case 14: + a13 = MP_DIGIT(a, 13); + case 13: + a12 = MP_DIGIT(a, 12); + case 12: + a11 = MP_DIGIT(a, 11); + case 11: + a10 = MP_DIGIT(a, 10); + case 10: + a9 = MP_DIGIT(a, 9); + case 9: + a8 = MP_DIGIT(a, 8); + } + + r0 = MP_DIGIT(a, 0); + r1 = MP_DIGIT(a, 1); + r2 = MP_DIGIT(a, 2); + r3 = MP_DIGIT(a, 3); + r4 = MP_DIGIT(a, 4); + r5 = MP_DIGIT(a, 5); + r6 = MP_DIGIT(a, 6); + r7 = MP_DIGIT(a, 7); + + /* sum 1 */ + carry = 0; + MP_ADD_CARRY(r3, a11, r3, carry); + MP_ADD_CARRY(r4, a12, r4, carry); + MP_ADD_CARRY(r5, a13, r5, carry); + MP_ADD_CARRY(r6, a14, r6, carry); + MP_ADD_CARRY(r7, a15, r7, carry); + r8 = carry; + carry = 0; + MP_ADD_CARRY(r3, a11, r3, carry); + MP_ADD_CARRY(r4, a12, r4, carry); + MP_ADD_CARRY(r5, a13, r5, carry); + MP_ADD_CARRY(r6, a14, r6, carry); + MP_ADD_CARRY(r7, a15, r7, carry); + r8 += carry; + carry = 0; + /* sum 2 */ + MP_ADD_CARRY(r3, a12, r3, carry); + MP_ADD_CARRY(r4, a13, r4, carry); + MP_ADD_CARRY(r5, a14, r5, carry); + MP_ADD_CARRY(r6, a15, r6, carry); + MP_ADD_CARRY(r7, 0, r7, carry); + r8 += carry; + carry = 0; + /* combine last bottom of sum 3 with second sum 2 */ + MP_ADD_CARRY(r0, a8, r0, carry); + MP_ADD_CARRY(r1, a9, r1, carry); + MP_ADD_CARRY(r2, a10, r2, carry); + MP_ADD_CARRY(r3, a12, r3, carry); + MP_ADD_CARRY(r4, a13, r4, carry); + MP_ADD_CARRY(r5, a14, r5, carry); + MP_ADD_CARRY(r6, a15, r6, carry); + MP_ADD_CARRY(r7, a15, r7, carry); /* from sum 3 */ + r8 += carry; + carry = 0; + /* sum 3 (rest of it)*/ + MP_ADD_CARRY(r6, a14, r6, carry); + MP_ADD_CARRY(r7, 0, r7, carry); + r8 += carry; + carry = 0; + /* sum 4 (rest of it)*/ + MP_ADD_CARRY(r0, a9, r0, carry); + MP_ADD_CARRY(r1, a10, r1, carry); + MP_ADD_CARRY(r2, a11, r2, carry); + MP_ADD_CARRY(r3, a13, r3, carry); + MP_ADD_CARRY(r4, a14, r4, carry); + MP_ADD_CARRY(r5, a15, r5, carry); + MP_ADD_CARRY(r6, a13, r6, carry); + MP_ADD_CARRY(r7, a8, r7, carry); + r8 += carry; + carry = 0; + /* diff 5 */ + MP_SUB_BORROW(r0, a11, r0, carry); + MP_SUB_BORROW(r1, a12, r1, carry); + MP_SUB_BORROW(r2, a13, r2, carry); + MP_SUB_BORROW(r3, 0, r3, carry); + MP_SUB_BORROW(r4, 0, r4, carry); + MP_SUB_BORROW(r5, 0, r5, carry); + MP_SUB_BORROW(r6, a8, r6, carry); + MP_SUB_BORROW(r7, a10, r7, carry); + r8 -= carry; + carry = 0; + /* diff 6 */ + MP_SUB_BORROW(r0, a12, r0, carry); + MP_SUB_BORROW(r1, a13, r1, carry); + MP_SUB_BORROW(r2, a14, r2, carry); + MP_SUB_BORROW(r3, a15, r3, carry); + MP_SUB_BORROW(r4, 0, r4, carry); + MP_SUB_BORROW(r5, 0, r5, carry); + MP_SUB_BORROW(r6, a9, r6, carry); + MP_SUB_BORROW(r7, a11, r7, carry); + r8 -= carry; + carry = 0; + /* diff 7 */ + MP_SUB_BORROW(r0, a13, r0, carry); + MP_SUB_BORROW(r1, a14, r1, carry); + MP_SUB_BORROW(r2, a15, r2, carry); + MP_SUB_BORROW(r3, a8, r3, carry); + MP_SUB_BORROW(r4, a9, r4, carry); + MP_SUB_BORROW(r5, a10, r5, carry); + MP_SUB_BORROW(r6, 0, r6, carry); + MP_SUB_BORROW(r7, a12, r7, carry); + r8 -= carry; + carry = 0; + /* diff 8 */ + MP_SUB_BORROW(r0, a14, r0, carry); + MP_SUB_BORROW(r1, a15, r1, carry); + MP_SUB_BORROW(r2, 0, r2, carry); + MP_SUB_BORROW(r3, a9, r3, carry); + MP_SUB_BORROW(r4, a10, r4, carry); + MP_SUB_BORROW(r5, a11, r5, carry); + MP_SUB_BORROW(r6, 0, r6, carry); + MP_SUB_BORROW(r7, a13, r7, carry); + r8 -= carry; + + /* reduce the overflows */ + while (r8 > 0) { + mp_digit r8_d = r8; + carry = 0; + MP_ADD_CARRY(r0, r8_d, r0, carry); + MP_ADD_CARRY(r1, 0, r1, carry); + MP_ADD_CARRY(r2, 0, r2, carry); + MP_ADD_CARRY(r3, 0 - r8_d, r3, carry); + MP_ADD_CARRY(r4, MP_DIGIT_MAX, r4, carry); + MP_ADD_CARRY(r5, MP_DIGIT_MAX, r5, carry); + MP_ADD_CARRY(r6, 0 - (r8_d + 1), r6, carry); + MP_ADD_CARRY(r7, (r8_d - 1), r7, carry); + r8 = carry; + } + + /* reduce the underflows */ + while (r8 < 0) { + mp_digit r8_d = -r8; + carry = 0; + MP_SUB_BORROW(r0, r8_d, r0, carry); + MP_SUB_BORROW(r1, 0, r1, carry); + MP_SUB_BORROW(r2, 0, r2, carry); + MP_SUB_BORROW(r3, 0 - r8_d, r3, carry); + MP_SUB_BORROW(r4, MP_DIGIT_MAX, r4, carry); + MP_SUB_BORROW(r5, MP_DIGIT_MAX, r5, carry); + MP_SUB_BORROW(r6, 0 - (r8_d + 1), r6, carry); + MP_SUB_BORROW(r7, (r8_d - 1), r7, carry); + r8 = 0 - carry; + } + if (a != r) { + MP_CHECKOK(s_mp_pad(r, 8)); + } + MP_SIGN(r) = MP_ZPOS; + MP_USED(r) = 8; + + MP_DIGIT(r, 7) = r7; + MP_DIGIT(r, 6) = r6; + MP_DIGIT(r, 5) = r5; + MP_DIGIT(r, 4) = r4; + MP_DIGIT(r, 3) = r3; + MP_DIGIT(r, 2) = r2; + MP_DIGIT(r, 1) = r1; + MP_DIGIT(r, 0) = r0; + + /* final reduction if necessary */ + if ((r7 == MP_DIGIT_MAX) && + ((r6 > 1) || ((r6 == 1) && + (r5 || r4 || r3 || + ((r2 == MP_DIGIT_MAX) && (r1 == MP_DIGIT_MAX) && (r0 == MP_DIGIT_MAX)))))) { + MP_CHECKOK(mp_sub(r, &meth->irr, r)); + } + + s_mp_clamp(r); +#else + switch (a_used) { + case 8: + a7 = MP_DIGIT(a, 7); + case 7: + a6 = MP_DIGIT(a, 6); + case 6: + a5 = MP_DIGIT(a, 5); + case 5: + a4 = MP_DIGIT(a, 4); + } + a7l = a7 << 32; + a7h = a7 >> 32; + a6l = a6 << 32; + a6h = a6 >> 32; + a5l = a5 << 32; + a5h = a5 >> 32; + a4l = a4 << 32; + a4h = a4 >> 32; + r3 = MP_DIGIT(a, 3); + r2 = MP_DIGIT(a, 2); + r1 = MP_DIGIT(a, 1); + r0 = MP_DIGIT(a, 0); + + /* sum 1 */ + carry = 0; + MP_ADD_CARRY(r1, a5h << 32, r1, carry); + MP_ADD_CARRY(r2, a6, r2, carry); + MP_ADD_CARRY(r3, a7, r3, carry); + r4 = carry; + carry = 0; + MP_ADD_CARRY(r1, a5h << 32, r1, carry); + MP_ADD_CARRY(r2, a6, r2, carry); + MP_ADD_CARRY(r3, a7, r3, carry); + r4 += carry; + /* sum 2 */ + carry = 0; + MP_ADD_CARRY(r1, a6l, r1, carry); + MP_ADD_CARRY(r2, a6h | a7l, r2, carry); + MP_ADD_CARRY(r3, a7h, r3, carry); + r4 += carry; + carry = 0; + MP_ADD_CARRY(r1, a6l, r1, carry); + MP_ADD_CARRY(r2, a6h | a7l, r2, carry); + MP_ADD_CARRY(r3, a7h, r3, carry); + r4 += carry; + + /* sum 3 */ + carry = 0; + MP_ADD_CARRY(r0, a4, r0, carry); + MP_ADD_CARRY(r1, a5l >> 32, r1, carry); + MP_ADD_CARRY(r2, 0, r2, carry); + MP_ADD_CARRY(r3, a7, r3, carry); + r4 += carry; + /* sum 4 */ + carry = 0; + MP_ADD_CARRY(r0, a4h | a5l, r0, carry); + MP_ADD_CARRY(r1, a5h | (a6h << 32), r1, carry); + MP_ADD_CARRY(r2, a7, r2, carry); + MP_ADD_CARRY(r3, a6h | a4l, r3, carry); + r4 += carry; + /* diff 5 */ + carry = 0; + MP_SUB_BORROW(r0, a5h | a6l, r0, carry); + MP_SUB_BORROW(r1, a6h, r1, carry); + MP_SUB_BORROW(r2, 0, r2, carry); + MP_SUB_BORROW(r3, (a4l >> 32) | a5l, r3, carry); + r4 -= carry; + /* diff 6 */ + carry = 0; + MP_SUB_BORROW(r0, a6, r0, carry); + MP_SUB_BORROW(r1, a7, r1, carry); + MP_SUB_BORROW(r2, 0, r2, carry); + MP_SUB_BORROW(r3, a4h | (a5h << 32), r3, carry); + r4 -= carry; + /* diff 7 */ + carry = 0; + MP_SUB_BORROW(r0, a6h | a7l, r0, carry); + MP_SUB_BORROW(r1, a7h | a4l, r1, carry); + MP_SUB_BORROW(r2, a4h | a5l, r2, carry); + MP_SUB_BORROW(r3, a6l, r3, carry); + r4 -= carry; + /* diff 8 */ + carry = 0; + MP_SUB_BORROW(r0, a7, r0, carry); + MP_SUB_BORROW(r1, a4h << 32, r1, carry); + MP_SUB_BORROW(r2, a5, r2, carry); + MP_SUB_BORROW(r3, a6h << 32, r3, carry); + r4 -= carry; + + /* reduce the overflows */ + while (r4 > 0) { + mp_digit r4_long = r4; + mp_digit r4l = (r4_long << 32); + carry = 0; + MP_ADD_CARRY(r0, r4_long, r0, carry); + MP_ADD_CARRY(r1, 0 - r4l, r1, carry); + MP_ADD_CARRY(r2, MP_DIGIT_MAX, r2, carry); + MP_ADD_CARRY(r3, r4l - r4_long - 1, r3, carry); + r4 = carry; + } + + /* reduce the underflows */ + while (r4 < 0) { + mp_digit r4_long = -r4; + mp_digit r4l = (r4_long << 32); + carry = 0; + MP_SUB_BORROW(r0, r4_long, r0, carry); + MP_SUB_BORROW(r1, 0 - r4l, r1, carry); + MP_SUB_BORROW(r2, MP_DIGIT_MAX, r2, carry); + MP_SUB_BORROW(r3, r4l - r4_long - 1, r3, carry); + r4 = 0 - carry; + } + + if (a != r) { + MP_CHECKOK(s_mp_pad(r, 4)); + } + MP_SIGN(r) = MP_ZPOS; + MP_USED(r) = 4; + + MP_DIGIT(r, 3) = r3; + MP_DIGIT(r, 2) = r2; + MP_DIGIT(r, 1) = r1; + MP_DIGIT(r, 0) = r0; + + /* final reduction if necessary */ + if ((r3 > 0xFFFFFFFF00000001ULL) || + ((r3 == 0xFFFFFFFF00000001ULL) && + (r2 || (r1 >> 32) || + (r1 == 0xFFFFFFFFULL && r0 == MP_DIGIT_MAX)))) { + /* very rare, just use mp_sub */ + MP_CHECKOK(mp_sub(r, &meth->irr, r)); + } + + s_mp_clamp(r); +#endif + } + +CLEANUP: + return res; +} + +/* Compute the square of polynomial a, reduce modulo p256. Store the + * result in r. r could be a. Uses optimized modular reduction for p256. + */ +static mp_err +ec_GFp_nistp256_sqr(const mp_int *a, mp_int *r, const GFMethod *meth) +{ + mp_err res = MP_OKAY; + + MP_CHECKOK(mp_sqr(a, r)); + MP_CHECKOK(ec_GFp_nistp256_mod(r, r, meth)); +CLEANUP: + return res; +} + +/* Compute the product of two polynomials a and b, reduce modulo p256. + * Store the result in r. r could be a or b; a could be b. Uses + * optimized modular reduction for p256. */ +static mp_err +ec_GFp_nistp256_mul(const mp_int *a, const mp_int *b, mp_int *r, + const GFMethod *meth) +{ + mp_err res = MP_OKAY; + + MP_CHECKOK(mp_mul(a, b, r)); + MP_CHECKOK(ec_GFp_nistp256_mod(r, r, meth)); +CLEANUP: + return res; +} + +/* Wire in fast field arithmetic and precomputation of base point for + * named curves. */ +mp_err +ec_group_set_gfp256(ECGroup *group, ECCurveName name) +{ + if (name == ECCurve_NIST_P256) { + group->meth->field_mod = &ec_GFp_nistp256_mod; + group->meth->field_mul = &ec_GFp_nistp256_mul; + group->meth->field_sqr = &ec_GFp_nistp256_sqr; + } + return MP_OKAY; +} |