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Commit bf03a404 authored by Jakub Pawlowski's avatar Jakub Pawlowski
Browse files

Get rid of KEY_LENGTH_DWORDS_P192 

Only KEY_LENGTH_DWORDS_P256 is used.

Test: compilation
Bug: 126463795
Change-Id: I32a80e4b012c4606a70994fa9d0b5c2602707bb3
parent 5e830f3a

system/stack/smp/p_256_curvepara.cc

+39 −43
Original line number Diff line number Diff line
@@ -25,11 +25,8 @@ 
#include <string.h>

#include "p_256_ecc_pp.h"



void p_256_init_curve(uint32_t keyLength) {

  elliptic_curve_t* ec;



  if (keyLength == KEY_LENGTH_DWORDS_P256) {

    ec = &curve_p256;

void p_256_init_curve() {

  elliptic_curve_t* ec = &curve_p256;



  ec->p[7] = 0xFFFFFFFF;

  ec->p[6] = 0x00000001;
@@ -74,4 +71,3 @@ void p_256_init_curve(uint32_t keyLength) { 
  ec->G.y[1] = 0xcbb64068;

  ec->G.y[0] = 0x37bf51f5;

}
 
}

system/stack/smp/p_256_ecc_pp.cc

+79 −86
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ static void p_256_copy_point(Point* q, Point* p) { 
}



// q=2q

static void ECC_Double(Point* q, Point* p, uint32_t keyLength) {

static void ECC_Double(Point* q, Point* p) {

  uint32_t t1[KEY_LENGTH_DWORDS_P256];

  uint32_t t2[KEY_LENGTH_DWORDS_P256];

  uint32_t t3[KEY_LENGTH_DWORDS_P256];
@@ -49,8 +49,8 @@ static void ECC_Double(Point* q, Point* p, uint32_t keyLength) { 
  uint32_t* z1;

  uint32_t* z3;



  if (multiprecision_iszero(p->z, keyLength)) {

    multiprecision_init(q->z, keyLength);

  if (multiprecision_iszero(p->z)) {

    multiprecision_init(q->z);

    return;  // return infinity

  }
@@ -61,33 +61,33 @@ static void ECC_Double(Point* q, Point* p, uint32_t keyLength) { 
  y3 = q->y;

  z3 = q->z;



  multiprecision_mersenns_squa_mod(t1, z1, keyLength);      // t1=z1^2

  multiprecision_sub_mod(t2, x1, t1, keyLength);            // t2=x1-t1

  multiprecision_add_mod(t1, x1, t1, keyLength);            // t1=x1+t1

  multiprecision_mersenns_mult_mod(t2, t1, t2, keyLength);  // t2=t2*t1

  multiprecision_lshift_mod(t3, t2, keyLength);

  multiprecision_add_mod(t2, t3, t2, keyLength);  // t2=3t2



  multiprecision_mersenns_mult_mod(z3, y1, z1, keyLength);  // z3=y1*z1

  multiprecision_lshift_mod(z3, z3, keyLength);



  multiprecision_mersenns_squa_mod(y3, y1, keyLength);  // y3=y1^2

  multiprecision_lshift_mod(y3, y3, keyLength);

  multiprecision_mersenns_mult_mod(t3, y3, x1, keyLength);  // t3=y3*x1=x1*y1^2

  multiprecision_lshift_mod(t3, t3, keyLength);

  multiprecision_mersenns_squa_mod(y3, y3, keyLength);  // y3=y3^2=y1^4

  multiprecision_lshift_mod(y3, y3, keyLength);



  multiprecision_mersenns_squa_mod(x3, t2, keyLength);      // x3=t2^2

  multiprecision_lshift_mod(t1, t3, keyLength);             // t1=2t3

  multiprecision_sub_mod(x3, x3, t1, keyLength);            // x3=x3-t1

  multiprecision_sub_mod(t1, t3, x3, keyLength);            // t1=t3-x3

  multiprecision_mersenns_mult_mod(t1, t1, t2, keyLength);  // t1=t1*t2

  multiprecision_sub_mod(y3, t1, y3, keyLength);            // y3=t1-y3

  multiprecision_mersenns_squa_mod(t1, z1);      // t1=z1^2

  multiprecision_sub_mod(t2, x1, t1);            // t2=x1-t1

  multiprecision_add_mod(t1, x1, t1);            // t1=x1+t1

  multiprecision_mersenns_mult_mod(t2, t1, t2);  // t2=t2*t1

  multiprecision_lshift_mod(t3, t2);

  multiprecision_add_mod(t2, t3, t2);  // t2=3t2



  multiprecision_mersenns_mult_mod(z3, y1, z1);  // z3=y1*z1

  multiprecision_lshift_mod(z3, z3);



  multiprecision_mersenns_squa_mod(y3, y1);  // y3=y1^2

  multiprecision_lshift_mod(y3, y3);

  multiprecision_mersenns_mult_mod(t3, y3, x1);  // t3=y3*x1=x1*y1^2

  multiprecision_lshift_mod(t3, t3);

  multiprecision_mersenns_squa_mod(y3, y3);  // y3=y3^2=y1^4

  multiprecision_lshift_mod(y3, y3);



  multiprecision_mersenns_squa_mod(x3, t2);      // x3=t2^2

  multiprecision_lshift_mod(t1, t3);             // t1=2t3

  multiprecision_sub_mod(x3, x3, t1);            // x3=x3-t1

  multiprecision_sub_mod(t1, t3, x3);            // t1=t3-x3

  multiprecision_mersenns_mult_mod(t1, t1, t2);  // t1=t1*t2

  multiprecision_sub_mod(y3, t1, y3);            // y3=t1-y3

}



// q=q+p,     zp must be 1

static void ECC_Add(Point* r, Point* p, Point* q, uint32_t keyLength) {

static void ECC_Add(Point* r, Point* p, Point* q) {

  uint32_t t1[KEY_LENGTH_DWORDS_P256];

  uint32_t t2[KEY_LENGTH_DWORDS_P256];

  uint32_t* x1;
@@ -111,58 +111,57 @@ static void ECC_Add(Point* r, Point* p, Point* q, uint32_t keyLength) { 
  z3 = r->z;



  // if Q=infinity, return p

  if (multiprecision_iszero(z2, keyLength)) {

  if (multiprecision_iszero(z2)) {

    p_256_copy_point(r, p);

    return;

  }



  // if P=infinity, return q

  if (multiprecision_iszero(z1, keyLength)) {

  if (multiprecision_iszero(z1)) {

    p_256_copy_point(r, q);

    return;

  }



  multiprecision_mersenns_squa_mod(t1, z1, keyLength);      // t1=z1^2

  multiprecision_mersenns_mult_mod(t2, z1, t1, keyLength);  // t2=t1*z1

  multiprecision_mersenns_mult_mod(t1, x2, t1, keyLength);  // t1=t1*x2

  multiprecision_mersenns_mult_mod(t2, y2, t2, keyLength);  // t2=t2*y2

  multiprecision_mersenns_squa_mod(t1, z1);      // t1=z1^2

  multiprecision_mersenns_mult_mod(t2, z1, t1);  // t2=t1*z1

  multiprecision_mersenns_mult_mod(t1, x2, t1);  // t1=t1*x2

  multiprecision_mersenns_mult_mod(t2, y2, t2);  // t2=t2*y2



  multiprecision_sub_mod(t1, t1, x1, keyLength);  // t1=t1-x1

  multiprecision_sub_mod(t2, t2, y1, keyLength);  // t2=t2-y1

  multiprecision_sub_mod(t1, t1, x1);  // t1=t1-x1

  multiprecision_sub_mod(t2, t2, y1);  // t2=t2-y1



  if (multiprecision_iszero(t1, keyLength)) {

    if (multiprecision_iszero(t2, keyLength)) {

      ECC_Double(r, q, keyLength);

  if (multiprecision_iszero(t1)) {

    if (multiprecision_iszero(t2)) {

      ECC_Double(r, q);

      return;

    } else {

      multiprecision_init(z3, keyLength);

      multiprecision_init(z3);

      return;  // return infinity

    }

  }



  multiprecision_mersenns_mult_mod(z3, z1, t1, keyLength);  // z3=z1*t1

  multiprecision_mersenns_squa_mod(y3, t1, keyLength);      // t3=t1^2

  multiprecision_mersenns_mult_mod(z1, y3, t1, keyLength);  // t4=t3*t1

  multiprecision_mersenns_mult_mod(y3, y3, x1, keyLength);  // t3=t3*x1

  multiprecision_lshift_mod(t1, y3, keyLength);             // t1=2*t3

  multiprecision_mersenns_squa_mod(x3, t2, keyLength);      // x3=t2^2

  multiprecision_sub_mod(x3, x3, t1, keyLength);            // x3=x3-t1

  multiprecision_sub_mod(x3, x3, z1, keyLength);            // x3=x3-t4

  multiprecision_sub_mod(y3, y3, x3, keyLength);            // t3=t3-x3

  multiprecision_mersenns_mult_mod(y3, y3, t2, keyLength);  // t3=t3*t2

  multiprecision_mersenns_mult_mod(z1, z1, y1, keyLength);  // t4=t4*t1

  multiprecision_sub_mod(y3, y3, z1, keyLength);

  multiprecision_mersenns_mult_mod(z3, z1, t1);  // z3=z1*t1

  multiprecision_mersenns_squa_mod(y3, t1);      // t3=t1^2

  multiprecision_mersenns_mult_mod(z1, y3, t1);  // t4=t3*t1

  multiprecision_mersenns_mult_mod(y3, y3, x1);  // t3=t3*x1

  multiprecision_lshift_mod(t1, y3);             // t1=2*t3

  multiprecision_mersenns_squa_mod(x3, t2);      // x3=t2^2

  multiprecision_sub_mod(x3, x3, t1);            // x3=x3-t1

  multiprecision_sub_mod(x3, x3, z1);            // x3=x3-t4

  multiprecision_sub_mod(y3, y3, x3);            // t3=t3-x3

  multiprecision_mersenns_mult_mod(y3, y3, t2);  // t3=t3*t2

  multiprecision_mersenns_mult_mod(z1, z1, y1);  // t4=t4*t1

  multiprecision_sub_mod(y3, y3, z1);

}



// Computing the Non-Adjacent Form of a positive integer

static void ECC_NAF(uint8_t* naf, uint32_t* NumNAF, uint32_t* k,

                    uint32_t keyLength) {

static void ECC_NAF(uint8_t* naf, uint32_t* NumNAF, uint32_t* k) {

  uint32_t sign;

  int i = 0;

  int j;

  uint32_t var;



  while ((var = multiprecision_most_signbits(k, keyLength)) >= 1) {

  while ((var = multiprecision_most_signbits(k)) >= 1) {

    if (k[0] & 0x01)  // k is odd

    {

      sign = (k[0] & 0x03);  // 1 or 3
@@ -183,7 +182,7 @@ static void ECC_NAF(uint8_t* naf, uint32_t* NumNAF, uint32_t* k, 
    } else

      sign = 0;



    multiprecision_rshift(k, k, keyLength);

    multiprecision_rshift(k, k);

    naf[i / 4] |= (sign) << ((i % 4) * 2);

    i++;

  }
@@ -192,8 +191,7 @@ static void ECC_NAF(uint8_t* naf, uint32_t* NumNAF, uint32_t* k, 
}



// Binary Non-Adjacent Form for point multiplication

void ECC_PointMult_Bin_NAF(Point* q, Point* p, uint32_t* n,

                           uint32_t keyLength) {

void ECC_PointMult_Bin_NAF(Point* q, Point* p, uint32_t* n) {

  uint32_t sign;

  uint8_t naf[256 / 4 + 1];

  uint32_t NumNaf;
@@ -201,69 +199,64 @@ void ECC_PointMult_Bin_NAF(Point* q, Point* p, uint32_t* n, 
  Point r;

  uint32_t* modp;



  if (keyLength == KEY_LENGTH_DWORDS_P256) {

  modp = curve_p256.p;

  } else {

    modp = curve.p;

  }



  p_256_init_point(&r);

  multiprecision_init(p->z, keyLength);

  multiprecision_init(p->z);

  p->z[0] = 1;



  // initialization

  p_256_init_point(q);



  // -p

  multiprecision_copy(minus_p.x, p->x, keyLength);

  multiprecision_sub(minus_p.y, modp, p->y, keyLength);

  multiprecision_copy(minus_p.x, p->x);

  multiprecision_sub(minus_p.y, modp, p->y);



  multiprecision_init(minus_p.z, keyLength);

  multiprecision_init(minus_p.z);

  minus_p.z[0] = 1;



  // NAF

  memset(naf, 0, sizeof(naf));

  ECC_NAF(naf, &NumNaf, n, keyLength);

  ECC_NAF(naf, &NumNaf, n);



  for (int i = NumNaf - 1; i >= 0; i--) {

    p_256_copy_point(&r, q);

    ECC_Double(q, &r, keyLength);

    ECC_Double(q, &r);

    sign = (naf[i / 4] >> ((i % 4) * 2)) & 0x03;



    if (sign == 1) {

      p_256_copy_point(&r, q);

      ECC_Add(q, &r, p, keyLength);

      ECC_Add(q, &r, p);

    } else if (sign == 3) {

      p_256_copy_point(&r, q);

      ECC_Add(q, &r, &minus_p, keyLength);

      ECC_Add(q, &r, &minus_p);

    }

  }



  multiprecision_inv_mod(minus_p.x, q->z, keyLength);

  multiprecision_mersenns_squa_mod(q->z, minus_p.x, keyLength);

  multiprecision_mersenns_mult_mod(q->x, q->x, q->z, keyLength);

  multiprecision_mersenns_mult_mod(q->z, q->z, minus_p.x, keyLength);

  multiprecision_mersenns_mult_mod(q->y, q->y, q->z, keyLength);

  multiprecision_inv_mod(minus_p.x, q->z);

  multiprecision_mersenns_squa_mod(q->z, minus_p.x);

  multiprecision_mersenns_mult_mod(q->x, q->x, q->z);

  multiprecision_mersenns_mult_mod(q->z, q->z, minus_p.x);

  multiprecision_mersenns_mult_mod(q->y, q->y, q->z);

}



bool ECC_ValidatePoint(const Point& pt) {

  const size_t kl = KEY_LENGTH_DWORDS_P256;

  p_256_init_curve(kl);

  p_256_init_curve();



  // Ensure y^2 = x^3 + a*x + b (mod p); a = -3



  // y^2 mod p

  uint32_t y2_mod[kl] = {0};

  multiprecision_mersenns_squa_mod(y2_mod, (uint32_t*)pt.y, kl);

  uint32_t y2_mod[KEY_LENGTH_DWORDS_P256] = {0};

  multiprecision_mersenns_squa_mod(y2_mod, (uint32_t*)pt.y);



  // Right hand side calculation

  uint32_t rhs[kl] = {0};

  multiprecision_mersenns_squa_mod(rhs, (uint32_t*)pt.x, kl);

  uint32_t three[kl] = {0};

  uint32_t rhs[KEY_LENGTH_DWORDS_P256] = {0};

  multiprecision_mersenns_squa_mod(rhs, (uint32_t*)pt.x);

  uint32_t three[KEY_LENGTH_DWORDS_P256] = {0};

  three[0] = 3;

  multiprecision_sub_mod(rhs, rhs, three, kl);

  multiprecision_mersenns_mult_mod(rhs, rhs, (uint32_t*)pt.x, kl);

  multiprecision_add_mod(rhs, rhs, curve_p256.b, kl);

  multiprecision_sub_mod(rhs, rhs, three);

  multiprecision_mersenns_mult_mod(rhs, rhs, (uint32_t*)pt.x);

  multiprecision_add_mod(rhs, rhs, curve_p256.b);



  return multiprecision_compare(rhs, y2_mod, kl) == 0;

  return multiprecision_compare(rhs, y2_mod) == 0;

}

system/stack/smp/p_256_ecc_pp.h

+3 −4
Original line number Diff line number Diff line
@@ -58,9 +58,8 @@ extern elliptic_curve_t curve_p256; 


bool ECC_ValidatePoint(const Point& p);



void ECC_PointMult_Bin_NAF(Point* q, Point* p, uint32_t* n, uint32_t keyLength);

void ECC_PointMult_Bin_NAF(Point* q, Point* p, uint32_t* n);



#define ECC_PointMult(q, p, n, keyLength) \

  ECC_PointMult_Bin_NAF(q, p, n, keyLength)

#define ECC_PointMult(q, p, n) ECC_PointMult_Bin_NAF(q, p, n)



void p_256_init_curve(uint32_t keyLength);
 
void p_256_init_curve();

system/stack/smp/p_256_multprecision.cc

+73 −183
Original line number Diff line number Diff line
@@ -27,24 +27,24 @@ 
#include "bt_target.h"

#include "p_256_ecc_pp.h"



void multiprecision_init(uint32_t* c, uint32_t keyLength) {

  for (uint32_t i = 0; i < keyLength; i++) c[i] = 0;

void multiprecision_init(uint32_t* c) {

  for (uint32_t i = 0; i < KEY_LENGTH_DWORDS_P256; i++) c[i] = 0;

}



void multiprecision_copy(uint32_t* c, uint32_t* a, uint32_t keyLength) {

  for (uint32_t i = 0; i < keyLength; i++) c[i] = a[i];

void multiprecision_copy(uint32_t* c, uint32_t* a) {

  for (uint32_t i = 0; i < KEY_LENGTH_DWORDS_P256; i++) c[i] = a[i];

}



int multiprecision_compare(uint32_t* a, uint32_t* b, uint32_t keyLength) {

  for (int i = keyLength - 1; i >= 0; i--) {

int multiprecision_compare(uint32_t* a, uint32_t* b) {

  for (int i = KEY_LENGTH_DWORDS_P256 - 1; i >= 0; i--) {

    if (a[i] > b[i]) return 1;

    if (a[i] < b[i]) return -1;

  }

  return 0;

}



int multiprecision_iszero(uint32_t* a, uint32_t keyLength) {

  for (uint32_t i = 0; i < keyLength; i++)

int multiprecision_iszero(uint32_t* a) {

  for (uint32_t i = 0; i < KEY_LENGTH_DWORDS_P256; i++)

    if (a[i]) return 0;



  return 1;
@@ -58,30 +58,29 @@ uint32_t multiprecision_dword_bits(uint32_t a) { 
  return i;

}



uint32_t multiprecision_most_signdwords(uint32_t* a, uint32_t keyLength) {

uint32_t multiprecision_most_signdwords(uint32_t* a) {

  int i;

  for (i = keyLength - 1; i >= 0; i--)

  for (i = KEY_LENGTH_DWORDS_P256 - 1; i >= 0; i--)

    if (a[i]) break;

  return (i + 1);

}



uint32_t multiprecision_most_signbits(uint32_t* a, uint32_t keyLength) {

uint32_t multiprecision_most_signbits(uint32_t* a) {

  int aMostSignDWORDs;



  aMostSignDWORDs = multiprecision_most_signdwords(a, keyLength);

  aMostSignDWORDs = multiprecision_most_signdwords(a);

  if (aMostSignDWORDs == 0) return 0;



  return (((aMostSignDWORDs - 1) << DWORD_BITS_SHIFT) +

          multiprecision_dword_bits(a[aMostSignDWORDs - 1]));

}



uint32_t multiprecision_add(uint32_t* c, uint32_t* a, uint32_t* b,

                            uint32_t keyLength) {

uint32_t multiprecision_add(uint32_t* c, uint32_t* a, uint32_t* b) {

  uint32_t carrier;

  uint32_t temp;



  carrier = 0;

  for (uint32_t i = 0; i < keyLength; i++) {

  for (uint32_t i = 0; i < KEY_LENGTH_DWORDS_P256; i++) {

    temp = a[i] + carrier;

    carrier = (temp < carrier);

    temp += b[i];
@@ -93,13 +92,12 @@ uint32_t multiprecision_add(uint32_t* c, uint32_t* a, uint32_t* b, 
}



// c=a-b

uint32_t multiprecision_sub(uint32_t* c, uint32_t* a, uint32_t* b,

                            uint32_t keyLength) {

uint32_t multiprecision_sub(uint32_t* c, uint32_t* a, uint32_t* b) {

  uint32_t borrow;

  uint32_t temp;



  borrow = 0;

  for (uint32_t i = 0; i < keyLength; i++) {

  for (uint32_t i = 0; i < KEY_LENGTH_DWORDS_P256; i++) {

    temp = a[i] - borrow;

    borrow = (temp > a[i]);

    c[i] = temp - b[i];
@@ -110,27 +108,20 @@ uint32_t multiprecision_sub(uint32_t* c, uint32_t* a, uint32_t* b, 
}



// c = a << 1

void multiprecision_lshift_mod(uint32_t* c, uint32_t* a, uint32_t keyLength) {

void multiprecision_lshift_mod(uint32_t* c, uint32_t* a) {

  uint32_t carrier;

  uint32_t* modp;



  if (keyLength == KEY_LENGTH_DWORDS_P192) {

    modp = curve.p;

  } else if (keyLength == KEY_LENGTH_DWORDS_P256) {

    modp = curve_p256.p;

  } else

    return;

  uint32_t* modp = curve_p256.p;



  carrier = multiprecision_lshift(c, a, keyLength);

  carrier = multiprecision_lshift(c, a);

  if (carrier) {

    multiprecision_sub(c, c, modp, keyLength);

  } else if (multiprecision_compare(c, modp, keyLength) >= 0) {

    multiprecision_sub(c, c, modp, keyLength);

    multiprecision_sub(c, c, modp);

  } else if (multiprecision_compare(c, modp) >= 0) {

    multiprecision_sub(c, c, modp);

  }

}



// c=a>>1

void multiprecision_rshift(uint32_t* c, uint32_t* a, uint32_t keyLength) {

void multiprecision_rshift(uint32_t* c, uint32_t* a) {

  int j;

  uint32_t b = 1;
@@ -138,7 +129,7 @@ void multiprecision_rshift(uint32_t* c, uint32_t* a, uint32_t keyLength) { 


  uint32_t carrier = 0;

  uint32_t temp;

  for (int i = keyLength - 1; i >= 0; i--) {

  for (int i = KEY_LENGTH_DWORDS_P256 - 1; i >= 0; i--) {

    temp = a[i];  // in case of c==a

    c[i] = (temp >> b) | carrier;

    carrier = temp << j;
@@ -147,64 +138,42 @@ void multiprecision_rshift(uint32_t* c, uint32_t* a, uint32_t keyLength) { 


// Curve specific optimization when p is a pseudo-Mersenns prime,

// p=2^(KEY_LENGTH_BITS)-omega

void multiprecision_mersenns_mult_mod(uint32_t* c, uint32_t* a, uint32_t* b,

                                      uint32_t keyLength) {

void multiprecision_mersenns_mult_mod(uint32_t* c, uint32_t* a, uint32_t* b) {

  uint32_t cc[2 * KEY_LENGTH_DWORDS_P256];



  multiprecision_mult(cc, a, b, keyLength);

  if (keyLength == 6) {

    multiprecision_fast_mod(c, cc);

  } else if (keyLength == 8) {

  multiprecision_mult(cc, a, b);

  multiprecision_fast_mod_P256(c, cc);

}

}



// Curve specific optimization when p is a pseudo-Mersenns prime

void multiprecision_mersenns_squa_mod(uint32_t* c, uint32_t* a,

                                      uint32_t keyLength) {

  multiprecision_mersenns_mult_mod(c, a, a, keyLength);

void multiprecision_mersenns_squa_mod(uint32_t* c, uint32_t* a) {

  multiprecision_mersenns_mult_mod(c, a, a);

}



// c=(a+b) mod p, b<p, a<p

void multiprecision_add_mod(uint32_t* c, uint32_t* a, uint32_t* b,

                            uint32_t keyLength) {

void multiprecision_add_mod(uint32_t* c, uint32_t* a, uint32_t* b) {

  uint32_t carrier;

  uint32_t* modp;



  if (keyLength == KEY_LENGTH_DWORDS_P192) {

    modp = curve.p;

  } else if (keyLength == KEY_LENGTH_DWORDS_P256) {

    modp = curve_p256.p;

  } else

    return;

  uint32_t* modp = curve_p256.p;



  carrier = multiprecision_add(c, a, b, keyLength);

  carrier = multiprecision_add(c, a, b);

  if (carrier) {

    multiprecision_sub(c, c, modp, keyLength);

  } else if (multiprecision_compare(c, modp, keyLength) >= 0) {

    multiprecision_sub(c, c, modp, keyLength);

    multiprecision_sub(c, c, modp);

  } else if (multiprecision_compare(c, modp) >= 0) {

    multiprecision_sub(c, c, modp);

  }

}



// c=(a-b) mod p, a<p, b<p

void multiprecision_sub_mod(uint32_t* c, uint32_t* a, uint32_t* b,

                            uint32_t keyLength) {

void multiprecision_sub_mod(uint32_t* c, uint32_t* a, uint32_t* b) {

  uint32_t borrow;

  uint32_t* modp;



  if (keyLength == KEY_LENGTH_DWORDS_P192) {

    modp = curve.p;

  } else if (keyLength == KEY_LENGTH_DWORDS_P256) {

    modp = curve_p256.p;

  } else

    return;

  uint32_t* modp = curve_p256.p;



  borrow = multiprecision_sub(c, a, b, keyLength);

  if (borrow) multiprecision_add(c, c, modp, keyLength);

  borrow = multiprecision_sub(c, a, b);

  if (borrow) multiprecision_add(c, c, modp);

}



// c=a<<b, b<DWORD_BITS, c has a buffer size of Numuint32_ts+1

uint32_t multiprecision_lshift(uint32_t* c, uint32_t* a, uint32_t keyLength) {

uint32_t multiprecision_lshift(uint32_t* c, uint32_t* a) {

  int j;

  uint32_t b = 1;

  j = DWORD_BITS - b;
@@ -212,7 +181,7 @@ uint32_t multiprecision_lshift(uint32_t* c, uint32_t* a, uint32_t keyLength) { 
  uint32_t carrier = 0;

  uint32_t temp;



  for (uint32_t i = 0; i < keyLength; i++) {

  for (uint32_t i = 0; i < KEY_LENGTH_DWORDS_P256; i++) {

    temp = a[i];  // in case c==a

    c[i] = (temp << b) | carrier;

    carrier = temp >> j;
@@ -222,19 +191,18 @@ uint32_t multiprecision_lshift(uint32_t* c, uint32_t* a, uint32_t keyLength) { 
}



// c=a*b; c must have a buffer of 2*Key_LENGTH_uint32_tS, c != a != b

void multiprecision_mult(uint32_t* c, uint32_t* a, uint32_t* b,

                         uint32_t keyLength) {

void multiprecision_mult(uint32_t* c, uint32_t* a, uint32_t* b) {

  uint32_t W;

  uint32_t U;

  uint32_t V;



  U = V = W = 0;

  multiprecision_init(c, keyLength);

  multiprecision_init(c);



  // assume little endian right now

  for (uint32_t i = 0; i < keyLength; i++) {

  for (uint32_t i = 0; i < KEY_LENGTH_DWORDS_P256; i++) {

    U = 0;

    for (uint32_t j = 0; j < keyLength; j++) {

    for (uint32_t j = 0; j < KEY_LENGTH_DWORDS_P256; j++) {

      uint64_t result;

      result = ((uint64_t)a[i]) * ((uint64_t)b[j]);

      W = result >> 32;
@@ -246,78 +214,7 @@ void multiprecision_mult(uint32_t* c, uint32_t* a, uint32_t* b, 
      U += (V < c[i + j]);

      c[i + j] = V;

    }

    c[i + keyLength] = U;

  }

}



void multiprecision_fast_mod(uint32_t* c, uint32_t* a) {

  uint32_t U;

  uint32_t V;

  uint32_t* modp = curve.p;



  c[0] = a[0] + a[6];

  U = c[0] < a[0];

  c[0] += a[10];

  U += c[0] < a[10];



  c[1] = a[1] + U;

  U = c[1] < a[1];

  c[1] += a[7];

  U += c[1] < a[7];

  c[1] += a[11];

  U += c[1] < a[11];



  c[2] = a[2] + U;

  U = c[2] < a[2];

  c[2] += a[6];

  U += c[2] < a[6];

  c[2] += a[8];

  U += c[2] < a[8];

  c[2] += a[10];

  U += c[2] < a[10];



  c[3] = a[3] + U;

  U = c[3] < a[3];

  c[3] += a[7];

  U += c[3] < a[7];

  c[3] += a[9];

  U += c[3] < a[9];

  c[3] += a[11];

  U += c[3] < a[11];



  c[4] = a[4] + U;

  U = c[4] < a[4];

  c[4] += a[8];

  U += c[4] < a[8];

  c[4] += a[10];

  U += c[4] < a[10];



  c[5] = a[5] + U;

  U = c[5] < a[5];

  c[5] += a[9];

  U += c[5] < a[9];

  c[5] += a[11];

  U += c[5] < a[11];



  c[0] += U;

  V = c[0] < U;

  c[1] += V;

  V = c[1] < V;

  c[2] += V;

  V = c[2] < V;

  c[2] += U;

  V = c[2] < U;

  c[3] += V;

  V = c[3] < V;

  c[4] += V;

  V = c[4] < V;

  c[5] += V;

  V = c[5] < V;



  if (V) {

    multiprecision_sub(c, c, modp, KEY_LENGTH_DWORDS_P192);

  } else if (multiprecision_compare(c, modp, KEY_LENGTH_DWORDS_P192) >= 0) {

    multiprecision_sub(c, c, modp, KEY_LENGTH_DWORDS_P192);

    c[i + KEY_LENGTH_DWORDS_P256] = U;

  }

}
@@ -541,74 +438,67 @@ void multiprecision_fast_mod_P256(uint32_t* c, uint32_t* a) { 


  if (U & 0x80000000) {

    while (U) {

      multiprecision_add(c, c, modp, KEY_LENGTH_DWORDS_P256);

      multiprecision_add(c, c, modp);

      U++;

    }

  } else if (U) {

    while (U) {

      multiprecision_sub(c, c, modp, KEY_LENGTH_DWORDS_P256);

      multiprecision_sub(c, c, modp);

      U--;

    }

  }



  if (multiprecision_compare(c, modp, KEY_LENGTH_DWORDS_P256) >= 0)

    multiprecision_sub(c, c, modp, KEY_LENGTH_DWORDS_P256);

  if (multiprecision_compare(c, modp) >= 0) multiprecision_sub(c, c, modp);

}



void multiprecision_inv_mod(uint32_t* aminus, uint32_t* u, uint32_t keyLength) {

void multiprecision_inv_mod(uint32_t* aminus, uint32_t* u) {

  uint32_t v[KEY_LENGTH_DWORDS_P256];

  uint32_t A[KEY_LENGTH_DWORDS_P256 + 1];

  uint32_t C[KEY_LENGTH_DWORDS_P256 + 1];

  uint32_t* modp;



  if (keyLength == KEY_LENGTH_DWORDS_P256) {

    modp = curve_p256.p;

  } else {

    modp = curve.p;

  }

  uint32_t* modp = curve_p256.p;



  multiprecision_copy(v, modp, keyLength);

  multiprecision_init(A, keyLength);

  multiprecision_init(C, keyLength);

  multiprecision_copy(v, modp);

  multiprecision_init(A);

  multiprecision_init(C);

  A[0] = 1;



  while (!multiprecision_iszero(u, keyLength)) {

  while (!multiprecision_iszero(u)) {

    while (!(u[0] & 0x01))  // u is even

    {

      multiprecision_rshift(u, u, keyLength);

      multiprecision_rshift(u, u);

      if (!(A[0] & 0x01))  // A is even

        multiprecision_rshift(A, A, keyLength);

        multiprecision_rshift(A, A);

      else {

        A[keyLength] = multiprecision_add(A, A, modp, keyLength);  // A =A+p

        multiprecision_rshift(A, A, keyLength);

        A[keyLength - 1] |= (A[keyLength] << 31);

        A[KEY_LENGTH_DWORDS_P256] = multiprecision_add(A, A, modp);  // A =A+p

        multiprecision_rshift(A, A);

        A[KEY_LENGTH_DWORDS_P256 - 1] |= (A[KEY_LENGTH_DWORDS_P256] << 31);

      }

    }



    while (!(v[0] & 0x01))  // v is even

    {

      multiprecision_rshift(v, v, keyLength);

      multiprecision_rshift(v, v);

      if (!(C[0] & 0x01))  // C is even

      {

        multiprecision_rshift(C, C, keyLength);

        multiprecision_rshift(C, C);

      } else {

        C[keyLength] = multiprecision_add(C, C, modp, keyLength);  // C =C+p

        multiprecision_rshift(C, C, keyLength);

        C[keyLength - 1] |= (C[keyLength] << 31);

        C[KEY_LENGTH_DWORDS_P256] = multiprecision_add(C, C, modp);  // C =C+p

        multiprecision_rshift(C, C);

        C[KEY_LENGTH_DWORDS_P256 - 1] |= (C[KEY_LENGTH_DWORDS_P256] << 31);

      }

    }



    if (multiprecision_compare(u, v, keyLength) >= 0) {

      multiprecision_sub(u, u, v, keyLength);

      multiprecision_sub_mod(A, A, C, keyLength);

    if (multiprecision_compare(u, v) >= 0) {

      multiprecision_sub(u, u, v);

      multiprecision_sub_mod(A, A, C);

    } else {

      multiprecision_sub(v, v, u, keyLength);

      multiprecision_sub_mod(C, C, A, keyLength);

      multiprecision_sub(v, v, u);

      multiprecision_sub_mod(C, C, A);

    }

  }



  if (multiprecision_compare(C, modp, keyLength) >= 0)

    multiprecision_sub(aminus, C, modp, keyLength);

  if (multiprecision_compare(C, modp) >= 0)

    multiprecision_sub(aminus, C, modp);

  else

    multiprecision_copy(aminus, C, keyLength);

    multiprecision_copy(aminus, C);

}

system/stack/smp/p_256_multprecision.h

+22 −33

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