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lightning-sunbird  0.9+nobinonly
Functions
ecp_256.c File Reference
#include "ecp.h"
#include "mpi.h"
#include "mplogic.h"
#include "mpi-priv.h"
#include <stdlib.h>

Go to the source code of this file.

Functions

mp_err ec_GFp_nistp256_mod (const mp_int *a, mp_int *r, const GFMethod *meth)
mp_err ec_GFp_nistp256_sqr (const mp_int *a, mp_int *r, const GFMethod *meth)
mp_err ec_GFp_nistp256_mul (const mp_int *a, const mp_int *b, mp_int *r, const GFMethod *meth)
mp_err ec_group_set_gfp256 (ECGroup *group, ECCurveName name)

Function Documentation

mp_err ec_GFp_nistp256_mod ( const mp_int a,
mp_int r,
const GFMethod *  meth 
)

Definition at line 49 of file ecp_256.c.

{
       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 */
              MP_ADD_CARRY(r3, a11, r3, 0,     carry);
              MP_ADD_CARRY(r4, a12, r4, carry, carry);
              MP_ADD_CARRY(r5, a13, r5, carry, carry);
              MP_ADD_CARRY(r6, a14, r6, carry, carry);
              MP_ADD_CARRY(r7, a15, r7, carry, carry);
              r8 = carry;
              MP_ADD_CARRY(r3, a11, r3, 0,     carry);
              MP_ADD_CARRY(r4, a12, r4, carry, carry);
              MP_ADD_CARRY(r5, a13, r5, carry, carry);
              MP_ADD_CARRY(r6, a14, r6, carry, carry);
              MP_ADD_CARRY(r7, a15, r7, carry, carry);
              r8 += carry;
              /* sum 2 */
              MP_ADD_CARRY(r3, a12, r3, 0,     carry);
              MP_ADD_CARRY(r4, a13, r4, carry, carry);
              MP_ADD_CARRY(r5, a14, r5, carry, carry);
              MP_ADD_CARRY(r6, a15, r6, carry, carry);
              MP_ADD_CARRY(r7,   0, r7, carry, carry);
              r8 += carry;
              /* combine last bottom of sum 3 with second sum 2 */
              MP_ADD_CARRY(r0, a8,  r0, 0,     carry);
              MP_ADD_CARRY(r1, a9,  r1, carry, carry);
              MP_ADD_CARRY(r2, a10, r2, carry, carry);
              MP_ADD_CARRY(r3, a12, r3, carry, carry);
              MP_ADD_CARRY(r4, a13, r4, carry, carry);
              MP_ADD_CARRY(r5, a14, r5, carry, carry);
              MP_ADD_CARRY(r6, a15, r6, carry, carry);
              MP_ADD_CARRY(r7, a15, r7, carry, carry); /* from sum 3 */
              r8 += carry;
              /* sum 3 (rest of it)*/
              MP_ADD_CARRY(r6, a14, r6, 0,     carry);
              MP_ADD_CARRY(r7,   0, r7, carry, carry);
              r8 += carry;
              /* sum 4 (rest of it)*/
              MP_ADD_CARRY(r0, a9,  r0, 0,     carry);
              MP_ADD_CARRY(r1, a10, r1, carry, carry);
              MP_ADD_CARRY(r2, a11, r2, carry, carry);
              MP_ADD_CARRY(r3, a13, r3, carry, carry);
              MP_ADD_CARRY(r4, a14, r4, carry, carry);
              MP_ADD_CARRY(r5, a15, r5, carry, carry);
              MP_ADD_CARRY(r6, a13, r6, carry, carry);
              MP_ADD_CARRY(r7, a8,  r7, carry, carry);
              r8 += carry;
              /* diff 5 */
              MP_SUB_BORROW(r0, a11, r0, 0,     carry);
              MP_SUB_BORROW(r1, a12, r1, carry, carry);
              MP_SUB_BORROW(r2, a13, r2, carry, carry);
              MP_SUB_BORROW(r3,   0, r3, carry, carry);
              MP_SUB_BORROW(r4,   0, r4, carry, carry);
              MP_SUB_BORROW(r5,   0, r5, carry, carry);
              MP_SUB_BORROW(r6, a8,  r6, carry, carry);
              MP_SUB_BORROW(r7, a10, r7, carry, carry);
              r8 -= carry;
              /* diff 6 */
              MP_SUB_BORROW(r0, a12, r0, 0,     carry);
              MP_SUB_BORROW(r1, a13, r1, carry, carry);
              MP_SUB_BORROW(r2, a14, r2, carry, carry);
              MP_SUB_BORROW(r3, a15, r3, carry, carry);
              MP_SUB_BORROW(r4,   0, r4, carry, carry);
              MP_SUB_BORROW(r5,   0, r5, carry, carry);
              MP_SUB_BORROW(r6, a9,  r6, carry, carry);
              MP_SUB_BORROW(r7, a11, r7, carry, carry);
              r8 -= carry;
              /* diff 7 */
              MP_SUB_BORROW(r0, a13, r0, 0,     carry);
              MP_SUB_BORROW(r1, a14, r1, carry, carry);
              MP_SUB_BORROW(r2, a15, r2, carry, carry);
              MP_SUB_BORROW(r3, a8,  r3, carry, carry);
              MP_SUB_BORROW(r4, a9,  r4, carry, carry);
              MP_SUB_BORROW(r5, a10, r5, carry, carry);
              MP_SUB_BORROW(r6, 0,   r6, carry, carry);
              MP_SUB_BORROW(r7, a12, r7, carry, carry);
              r8 -= carry;
              /* diff 8 */
              MP_SUB_BORROW(r0, a14, r0, 0,     carry);
              MP_SUB_BORROW(r1, a15, r1, carry, carry);
              MP_SUB_BORROW(r2, 0,   r2, carry, carry);
              MP_SUB_BORROW(r3, a9,  r3, carry, carry);
              MP_SUB_BORROW(r4, a10, r4, carry, carry);
              MP_SUB_BORROW(r5, a11, r5, carry, carry);
              MP_SUB_BORROW(r6, 0,   r6, carry, carry);
              MP_SUB_BORROW(r7, a13, r7, carry, carry);
              r8 -= carry;

              /* reduce the overflows */
              while (r8 > 0) {
                     mp_digit r8_d = r8;
                     MP_ADD_CARRY(r0, r8_d,         r0, 0,     carry);
                     MP_ADD_CARRY(r1, 0,            r1, carry, carry);
                     MP_ADD_CARRY(r2, 0,            r2, carry, carry);
                     MP_ADD_CARRY(r3, -r8_d,        r3, carry, carry);
                     MP_ADD_CARRY(r4, MP_DIGIT_MAX, r4, carry, carry);
                     MP_ADD_CARRY(r5, MP_DIGIT_MAX, r5, carry, carry);
                     MP_ADD_CARRY(r6, -(r8_d+1),    r6, carry, carry);
                     MP_ADD_CARRY(r7, (r8_d-1),     r7, carry, carry);
                     r8 = carry;
              }

              /* reduce the underflows */
              while (r8 < 0) {
                     mp_digit r8_d = -r8;
                     MP_SUB_BORROW(r0, r8_d,         r0, 0,     carry);
                     MP_SUB_BORROW(r1, 0,            r1, carry, carry);
                     MP_SUB_BORROW(r2, 0,            r2, carry, carry);
                     MP_SUB_BORROW(r3, -r8_d,        r3, carry, carry);
                     MP_SUB_BORROW(r4, MP_DIGIT_MAX, r4, carry, carry);
                     MP_SUB_BORROW(r5, MP_DIGIT_MAX, r5, carry, carry);
                     MP_SUB_BORROW(r6, -(r8_d+1),    r6, carry, carry);
                     MP_SUB_BORROW(r7, (r8_d-1),     r7, carry, carry);
                     r8 = -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));
              }
#ifdef notdef
                     

              /* smooth the negatives */
              while (MP_SIGN(r) != MP_ZPOS) {
                     MP_CHECKOK(mp_add(r, &meth->irr, r));
              }
              while (MP_USED(r) > 8) {
                     MP_CHECKOK(mp_sub(r, &meth->irr, r));
              }

              /* final reduction if necessary */
              if (MP_DIGIT(r,7) >= MP_DIGIT(&meth->irr,7)) {
                  if (mp_cmp(r,&meth->irr) != MP_LT) {
                     MP_CHECKOK(mp_sub(r, &meth->irr, r));
                  }
              }
#endif
              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 */
              MP_ADD_CARRY(r1, a5h << 32, r1, 0,     carry);
              MP_ADD_CARRY(r2, a6,        r2, carry, carry);
              MP_ADD_CARRY(r3, a7,        r3, carry, carry);
              r4 = carry;
              MP_ADD_CARRY(r1, a5h << 32, r1, 0,     carry);
              MP_ADD_CARRY(r2, a6,        r2, carry, carry);
              MP_ADD_CARRY(r3, a7,        r3, carry, carry);
              r4 += carry;
              /* sum 2 */
              MP_ADD_CARRY(r1, a6l,       r1, 0,     carry);
              MP_ADD_CARRY(r2, a6h | a7l, r2, carry, carry);
              MP_ADD_CARRY(r3, a7h,       r3, carry, carry);
              r4 += carry;
              MP_ADD_CARRY(r1, a6l,       r1, 0,     carry);
              MP_ADD_CARRY(r2, a6h | a7l, r2, carry, carry);
              MP_ADD_CARRY(r3, a7h,       r3, carry, carry);
              r4 += carry;

              /* sum 3 */
              MP_ADD_CARRY(r0, a4,        r0, 0,     carry);
              MP_ADD_CARRY(r1, a5l >> 32, r1, carry, carry);
              MP_ADD_CARRY(r2, 0,         r2, carry, carry);
              MP_ADD_CARRY(r3, a7,        r3, carry, carry);
              r4 += carry;
              /* sum 4 */
              MP_ADD_CARRY(r0, a4h | a5l,     r0, 0,     carry);
              MP_ADD_CARRY(r1, a5h|(a6h<<32), r1, carry, carry);
              MP_ADD_CARRY(r2, a7,            r2, carry, carry);
              MP_ADD_CARRY(r3, a6h | a4l,     r3, carry, carry);
              r4 += carry;
              /* diff 5 */
              MP_SUB_BORROW(r0, a5h | a6l,    r0, 0,     carry);
              MP_SUB_BORROW(r1, a6h,          r1, carry, carry);
              MP_SUB_BORROW(r2, 0,            r2, carry, carry);
              MP_SUB_BORROW(r3, (a4l>>32)|a5l,r3, carry, carry);
              r4 -= carry;
              /* diff 6 */
              MP_SUB_BORROW(r0, a6,              r0, 0,     carry);
              MP_SUB_BORROW(r1, a7,           r1, carry, carry);
              MP_SUB_BORROW(r2, 0,            r2, carry, carry);
              MP_SUB_BORROW(r3, a4h|(a5h<<32),r3, carry, carry);
              r4 -= carry;
              /* diff 7 */
              MP_SUB_BORROW(r0, a6h|a7l,  r0, 0,     carry);
              MP_SUB_BORROW(r1, a7h|a4l,      r1, carry, carry);
              MP_SUB_BORROW(r2, a4h|a5l,      r2, carry, carry);
              MP_SUB_BORROW(r3, a6l,          r3, carry, carry);
              r4 -= carry;
              /* diff 8 */
              MP_SUB_BORROW(r0, a7,               r0, 0,     carry);
              MP_SUB_BORROW(r1, a4h<<32,      r1, carry, carry);
              MP_SUB_BORROW(r2, a5,           r2, carry, carry);
              MP_SUB_BORROW(r3, a6h<<32,      r3, carry, carry);
              r4 -= carry;

              /* reduce the overflows */
              while (r4 > 0) {
                     mp_digit r4_long = r4;
                     mp_digit r4l = (r4_long << 32);
                     MP_ADD_CARRY(r0, r4_long,      r0, 0,     carry);
                     MP_ADD_CARRY(r1, -r4l,         r1, carry, carry);
                     MP_ADD_CARRY(r2, MP_DIGIT_MAX, r2, carry, carry);
                     MP_ADD_CARRY(r3, r4l-r4_long-1,r3, carry, carry);
                     r4 = carry;
              }

              /* reduce the underflows */
              while (r4 < 0) {
                     mp_digit r4_long = -r4;
                     mp_digit r4l = (r4_long << 32);
                     MP_SUB_BORROW(r0, r4_long,      r0, 0,     carry);
                     MP_SUB_BORROW(r1, -r4l,         r1, carry, carry);
                     MP_SUB_BORROW(r2, MP_DIGIT_MAX, r2, carry, carry);
                     MP_SUB_BORROW(r3, r4l-r4_long-1,r3, carry, carry);
                     r4 = -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;
}

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mp_err ec_GFp_nistp256_mul ( const mp_int a,
const mp_int b,
mp_int r,
const GFMethod *  meth 
)

Definition at line 407 of file ecp_256.c.

{
       mp_err res = MP_OKAY;

       MP_CHECKOK(mp_mul(a, b, r));
       MP_CHECKOK(ec_GFp_nistp256_mod(r, r, meth));
  CLEANUP:
       return res;
}

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mp_err ec_GFp_nistp256_sqr ( const mp_int a,
mp_int r,
const GFMethod *  meth 
)

Definition at line 393 of file ecp_256.c.

{
       mp_err res = MP_OKAY;

       MP_CHECKOK(mp_sqr(a, r));
       MP_CHECKOK(ec_GFp_nistp256_mod(r, r, meth));
  CLEANUP:
       return res;
}

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mp_err ec_group_set_gfp256 ( ECGroup *  group,
ECCurveName  name 
)

Definition at line 421 of file ecp_256.c.

{
       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;
}

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