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lightning-sunbird  0.9+nobinonly
Defines | Functions
ecp_224.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.

Defines

#define ECP224_DIGITS   ECL_CURVE_DIGITS(224)

Functions

mp_err ec_GFp_nistp224_mod (const mp_int *a, mp_int *r, const GFMethod *meth)
mp_err ec_GFp_nistp224_sqr (const mp_int *a, mp_int *r, const GFMethod *meth)
mp_err ec_GFp_nistp224_mul (const mp_int *a, const mp_int *b, mp_int *r, const GFMethod *meth)
mp_err ec_GFp_nistp224_div (const mp_int *a, const mp_int *b, mp_int *r, const GFMethod *meth)
mp_err ec_group_set_gfp224 (ECGroup *group, ECCurveName name)

Define Documentation

Definition at line 45 of file ecp_224.c.


Function Documentation

mp_err ec_GFp_nistp224_div ( const mp_int a,
const mp_int b,
mp_int r,
const GFMethod *  meth 
)

Definition at line 338 of file ecp_224.c.

{
       mp_err res = MP_OKAY;
       mp_int t;

       /* If a is NULL, then return the inverse of b, otherwise return a/b. */
       if (a == NULL) {
              return  mp_invmod(b, &meth->irr, r);
       } else {
              /* MPI doesn't support divmod, so we implement it using invmod and 
               * mulmod. */
              MP_CHECKOK(mp_init(&t));
              MP_CHECKOK(mp_invmod(b, &meth->irr, &t));
              MP_CHECKOK(mp_mul(a, &t, r));
              MP_CHECKOK(ec_GFp_nistp224_mod(r, r, meth));
         CLEANUP:
              mp_clear(&t);
              return res;
       }
}

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mp_err ec_GFp_nistp224_mod ( const mp_int a,
mp_int r,
const GFMethod *  meth 
)

Definition at line 51 of file ecp_224.c.

{
       mp_err res = MP_OKAY;
       mp_size a_used = MP_USED(a);

       int    r3b;
       mp_digit carry;
#ifdef ECL_THIRTY_TWO_BIT
        mp_digit a6a = 0, a6b = 0,
                a5a = 0, a5b = 0, a4a = 0, a4b = 0, a3a = 0, a3b = 0;
        mp_digit r0a, r0b, r1a, r1b, r2a, r2b, r3a;
#else
       mp_digit a6 = 0, a5 = 0, a4 = 0, a3b = 0, a5a = 0;
        mp_digit a6b = 0, a6a_a5b = 0, a5b = 0, a5a_a4b = 0, a4a_a3b = 0;
        mp_digit r0, r1, r2, r3;
#endif

       /* reduction not needed if a is not larger than field size */
       if (a_used < ECP224_DIGITS) {
              if (a == r) return MP_OKAY;
              return mp_copy(a, r);
       }
       /* for polynomials larger than twice the field size, use regular
        * reduction */
       if (a_used > ECL_CURVE_DIGITS(224*2)) {
              MP_CHECKOK(mp_mod(a, &meth->irr, r));
       } else {
#ifdef ECL_THIRTY_TWO_BIT
              /* copy out upper words of a */
              switch (a_used) {
              case 14:
                     a6b = MP_DIGIT(a, 13);
              case 13:
                     a6a = MP_DIGIT(a, 12);
              case 12:
                     a5b = MP_DIGIT(a, 11);
              case 11:
                     a5a = MP_DIGIT(a, 10);
              case 10:
                     a4b = MP_DIGIT(a, 9);
              case 9:
                     a4a = MP_DIGIT(a, 8);
              case 8:
                     a3b = MP_DIGIT(a, 7);
              }
              r3a = MP_DIGIT(a, 6);
              r2b= MP_DIGIT(a, 5);
              r2a= MP_DIGIT(a, 4);
              r1b = MP_DIGIT(a, 3);
              r1a = MP_DIGIT(a, 2);
              r0b = MP_DIGIT(a, 1);
              r0a = MP_DIGIT(a, 0);


              /* implement r = (a3a,a2,a1,a0)
                     +(a5a, a4,a3b,  0)
                     +(  0, a6,a5b,  0)
                     -(  0   0,    0|a6b, a6a|a5b )
                     -(  a6b, a6a|a5b, a5a|a4b, a4a|a3b ) */
              MP_ADD_CARRY (r1b, a3b, r1b, 0,     carry);
              MP_ADD_CARRY (r2a, a4a, r2a, carry, carry);
              MP_ADD_CARRY (r2b, a4b, r2b, carry, carry);
              MP_ADD_CARRY (r3a, a5a, r3a, carry, carry);
              r3b = carry;
              MP_ADD_CARRY (r1b, a5b, r1b, 0,     carry);
              MP_ADD_CARRY (r2a, a6a, r2a, carry, carry);
              MP_ADD_CARRY (r2b, a6b, r2b, carry, carry);
              MP_ADD_CARRY (r3a,   0, r3a, carry, carry);
              r3b += carry;
              MP_SUB_BORROW(r0a, a3b, r0a, 0,     carry);
              MP_SUB_BORROW(r0b, a4a, r0b, carry, carry);
              MP_SUB_BORROW(r1a, a4b, r1a, carry, carry);
              MP_SUB_BORROW(r1b, a5a, r1b, carry, carry);
              MP_SUB_BORROW(r2a, a5b, r2a, carry, carry);
              MP_SUB_BORROW(r2b, a6a, r2b, carry, carry);
              MP_SUB_BORROW(r3a, a6b, r3a, carry, carry);
              r3b -= carry;
              MP_SUB_BORROW(r0a, a5b, r0a, 0,     carry);
              MP_SUB_BORROW(r0b, a6a, r0b, carry, carry);
              MP_SUB_BORROW(r1a, a6b, r1a, carry, carry);
              if (carry) {
                     MP_SUB_BORROW(r1b, 0, r1b, carry, carry);
                     MP_SUB_BORROW(r2a, 0, r2a, carry, carry);
                     MP_SUB_BORROW(r2b, 0, r2b, carry, carry);
                     MP_SUB_BORROW(r3a, 0, r3a, carry, carry);
                     r3b -= carry;
              }

              while (r3b > 0) {
                     int tmp;
                     MP_ADD_CARRY(r1b, r3b, r1b, 0,     carry);
                     if (carry) {
                            MP_ADD_CARRY(r2a,  0, r2a, carry, carry);
                            MP_ADD_CARRY(r2b,  0, r2b, carry, carry);
                            MP_ADD_CARRY(r3a,  0, r3a, carry, carry);
                     }
                     tmp = carry;
                     MP_SUB_BORROW(r0a, r3b, r0a, 0,     carry);
                     if (carry) {
                            MP_SUB_BORROW(r0b, 0, r0b, carry, carry);
                            MP_SUB_BORROW(r1a, 0, r1a, carry, carry);
                            MP_SUB_BORROW(r1b, 0, r1b, carry, carry);
                            MP_SUB_BORROW(r2a, 0, r2a, carry, carry);
                            MP_SUB_BORROW(r2b, 0, r2b, carry, carry);
                            MP_SUB_BORROW(r3a, 0, r3a, carry, carry);
                            tmp -= carry;
                     }
                     r3b = tmp;
              }

              while (r3b < 0) {
                     mp_digit maxInt = MP_DIGIT_MAX;
                     MP_ADD_CARRY (r0a, 1, r0a, 0,     carry);
                     MP_ADD_CARRY (r0b, 0, r0b, carry, carry);
                     MP_ADD_CARRY (r1a, 0, r1a, carry, carry);
                     MP_ADD_CARRY (r1b, maxInt, r1b, carry, carry);
                     MP_ADD_CARRY (r2a, maxInt, r2a, carry, carry);
                     MP_ADD_CARRY (r2b, maxInt, r2b, carry, carry);
                     MP_ADD_CARRY (r3a, maxInt, r3a, carry, carry);
                     r3b += carry;
              }
              /* check for final reduction */
              /* now the only way we are over is if the top 4 words are all ones */
              if ((r3a == MP_DIGIT_MAX) && (r2b == MP_DIGIT_MAX)
                     && (r2a == MP_DIGIT_MAX) && (r1b == MP_DIGIT_MAX) &&
                      ((r1a != 0) || (r0b != 0) || (r0a != 0)) ) {
                     /* one last subraction */
                     MP_SUB_BORROW(r0a, 1, r0a, 0,     carry);
                     MP_SUB_BORROW(r0b, 0, r0b, carry, carry);
                     MP_SUB_BORROW(r1a, 0, r1a, carry, carry);
                     r1b = r2a = r2b = r3a = 0;
              }


              if (a != r) {
                     MP_CHECKOK(s_mp_pad(r, 7));
              }
              /* set the lower words of r */
              MP_SIGN(r) = MP_ZPOS;
              MP_USED(r) = 7;
              MP_DIGIT(r, 6) = r3a;
              MP_DIGIT(r, 5) = r2b;
              MP_DIGIT(r, 4) = r2a;
              MP_DIGIT(r, 3) = r1b;
              MP_DIGIT(r, 2) = r1a;
              MP_DIGIT(r, 1) = r0b;
              MP_DIGIT(r, 0) = r0a;
#else
              /* copy out upper words of a */
              switch (a_used) {
              case 7:
                     a6 = MP_DIGIT(a, 6);
                     a6b = a6 >> 32;
                     a6a_a5b = a6 << 32;
              case 6:
                     a5 = MP_DIGIT(a, 5);
                     a5b = a5 >> 32;
                     a6a_a5b |= a5b;
                     a5b = a5b << 32;
                     a5a_a4b = a5 << 32;
                     a5a = a5 & 0xffffffff;
              case 5:
                     a4 = MP_DIGIT(a, 4);
                     a5a_a4b |= a4 >> 32;
                     a4a_a3b = a4 << 32;
              case 4:
                     a3b = MP_DIGIT(a, 3) >> 32;
                     a4a_a3b |= a3b;
                     a3b = a3b << 32;
              }

              r3 = MP_DIGIT(a, 3) & 0xffffffff;
              r2 = MP_DIGIT(a, 2);
              r1 = MP_DIGIT(a, 1);
              r0 = MP_DIGIT(a, 0);

              /* implement r = (a3a,a2,a1,a0)
                     +(a5a, a4,a3b,  0)
                     +(  0, a6,a5b,  0)
                     -(  0   0,    0|a6b, a6a|a5b )
                     -(  a6b, a6a|a5b, a5a|a4b, a4a|a3b ) */
              MP_ADD_CARRY (r1, a3b, r1, 0,     carry);
              MP_ADD_CARRY (r2, a4 , r2, carry, carry);
              MP_ADD_CARRY (r3, a5a, r3, carry, carry);
              MP_ADD_CARRY (r1, a5b, r1, 0,     carry);
              MP_ADD_CARRY (r2, a6 , r2, carry, carry);
              MP_ADD_CARRY (r3,   0, r3, carry, carry);

              MP_SUB_BORROW(r0, a4a_a3b, r0, 0,     carry);
              MP_SUB_BORROW(r1, a5a_a4b, r1, carry, carry);
              MP_SUB_BORROW(r2, a6a_a5b, r2, carry, carry);
              MP_SUB_BORROW(r3, a6b    , r3, carry, carry);
              MP_SUB_BORROW(r0, a6a_a5b, r0, 0,     carry);
              MP_SUB_BORROW(r1, a6b    , r1, carry, carry);
              if (carry) {
                     MP_SUB_BORROW(r2, 0, r2, carry, carry);
                     MP_SUB_BORROW(r3, 0, r3, carry, carry);
              }


              /* if the value is negative, r3 has a 2's complement 
               * high value */
              r3b = (int)(r3 >>32);
              while (r3b > 0) {
                     r3 &= 0xffffffff;
                     MP_ADD_CARRY(r1,((mp_digit)r3b) << 32, r1, 0, carry);
                     if (carry) {
                            MP_ADD_CARRY(r2,  0, r2, carry, carry);
                            MP_ADD_CARRY(r3,  0, r3, carry, carry);
                     }
                     MP_SUB_BORROW(r0, r3b, r0, 0, carry);
                     if (carry) {
                            MP_SUB_BORROW(r1, 0, r1, carry, carry);
                            MP_SUB_BORROW(r2, 0, r2, carry, carry);
                            MP_SUB_BORROW(r3, 0, r3, carry, carry);
                     }
                     r3b = (int)(r3 >>32);
              }

              while (r3b < 0) {
                     MP_ADD_CARRY (r0, 1, r0, 0,     carry);
                     MP_ADD_CARRY (r1, MP_DIGIT_MAX <<32, r1, carry, carry);
                     MP_ADD_CARRY (r2, MP_DIGIT_MAX, r2, carry, carry);
                     MP_ADD_CARRY (r3, MP_DIGIT_MAX >> 32, r3, carry, carry);
                     r3b = (int)(r3 >>32);
              }
              /* check for final reduction */
              /* now the only way we are over is if the top 4 words are all ones */
              if ((r3 == (MP_DIGIT_MAX >> 32)) && (r2 == MP_DIGIT_MAX)
                     && ((r1 & MP_DIGIT_MAX << 32)== MP_DIGIT_MAX << 32) &&
                      ((r1 != MP_DIGIT_MAX << 32 ) || (r0 != 0)) ) {
                     /* one last subraction */
                     MP_SUB_BORROW(r0, 1, r0, 0,     carry);
                     MP_SUB_BORROW(r1, 0, r1, carry, carry);
                     r2 = r3 = 0;
              }


              if (a != r) {
                     MP_CHECKOK(s_mp_pad(r, 4));
              }
              /* set the lower words of r */
              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;
#endif
       }

  CLEANUP:
       return res;
}

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mp_err ec_GFp_nistp224_mul ( const mp_int a,
const mp_int b,
mp_int r,
const GFMethod *  meth 
)

Definition at line 324 of file ecp_224.c.

{
       mp_err res = MP_OKAY;

       MP_CHECKOK(mp_mul(a, b, r));
       MP_CHECKOK(ec_GFp_nistp224_mod(r, r, meth));
  CLEANUP:
       return res;
}

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mp_err ec_GFp_nistp224_sqr ( const mp_int a,
mp_int r,
const GFMethod *  meth 
)

Definition at line 310 of file ecp_224.c.

{
       mp_err res = MP_OKAY;

       MP_CHECKOK(mp_sqr(a, r));
       MP_CHECKOK(ec_GFp_nistp224_mod(r, r, meth));
  CLEANUP:
       return res;
}

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mp_err ec_group_set_gfp224 ( ECGroup *  group,
ECCurveName  name 
)

Definition at line 363 of file ecp_224.c.

{
       if (name == ECCurve_NIST_P224) {
              group->meth->field_mod = &ec_GFp_nistp224_mod;
              group->meth->field_mul = &ec_GFp_nistp224_mul;
              group->meth->field_sqr = &ec_GFp_nistp224_sqr;
              group->meth->field_div = &ec_GFp_nistp224_div;
       }
       return MP_OKAY;
}