Cache the values of curve->num_words and curve->num_n_words. Apparently the optimizer is not as smart as I thought.
diff --git a/curve-specific.inc b/curve-specific.inc index fa9a7dc..7ce7e4d 100644 --- a/curve-specific.inc +++ b/curve-specific.inc
@@ -58,8 +58,9 @@ /* t1 = X, t2 = Y, t3 = Z */ uECC_word_t t4[uECC_MAX_WORDS]; uECC_word_t t5[uECC_MAX_WORDS]; + wordcount_t num_words = curve->num_words; - if (uECC_vli_isZero(Z1, curve->num_words)) { + if (uECC_vli_isZero(Z1, num_words)) { return; } @@ -69,32 +70,32 @@ uECC_vli_modMult_fast(Y1, Y1, Z1, curve); /* t2 = y1*z1 = z3 */ uECC_vli_modSquare_fast(Z1, Z1, curve); /* t3 = z1^2 */ - uECC_vli_modAdd(X1, X1, Z1, curve->p, curve->num_words); /* t1 = x1 + z1^2 */ - uECC_vli_modAdd(Z1, Z1, Z1, curve->p, curve->num_words); /* t3 = 2*z1^2 */ - uECC_vli_modSub(Z1, X1, Z1, curve->p, curve->num_words); /* t3 = x1 - z1^2 */ + uECC_vli_modAdd(X1, X1, Z1, curve->p, num_words); /* t1 = x1 + z1^2 */ + uECC_vli_modAdd(Z1, Z1, Z1, curve->p, num_words); /* t3 = 2*z1^2 */ + uECC_vli_modSub(Z1, X1, Z1, curve->p, num_words); /* t3 = x1 - z1^2 */ uECC_vli_modMult_fast(X1, X1, Z1, curve); /* t1 = x1^2 - z1^4 */ - uECC_vli_modAdd(Z1, X1, X1, curve->p, curve->num_words); /* t3 = 2*(x1^2 - z1^4) */ - uECC_vli_modAdd(X1, X1, Z1, curve->p, curve->num_words); /* t1 = 3*(x1^2 - z1^4) */ + uECC_vli_modAdd(Z1, X1, X1, curve->p, num_words); /* t3 = 2*(x1^2 - z1^4) */ + uECC_vli_modAdd(X1, X1, Z1, curve->p, num_words); /* t1 = 3*(x1^2 - z1^4) */ if (uECC_vli_testBit(X1, 0)) { - uECC_word_t l_carry = uECC_vli_add(X1, X1, curve->p, curve->num_words); - uECC_vli_rshift1(X1, curve->num_words); - X1[curve->num_words - 1] |= l_carry << (uECC_WORD_BITS - 1); + uECC_word_t l_carry = uECC_vli_add(X1, X1, curve->p, num_words); + uECC_vli_rshift1(X1, num_words); + X1[num_words - 1] |= l_carry << (uECC_WORD_BITS - 1); } else { - uECC_vli_rshift1(X1, curve->num_words); + uECC_vli_rshift1(X1, num_words); } /* t1 = 3/2*(x1^2 - z1^4) = B */ uECC_vli_modSquare_fast(Z1, X1, curve); /* t3 = B^2 */ - uECC_vli_modSub(Z1, Z1, t5, curve->p, curve->num_words); /* t3 = B^2 - A */ - uECC_vli_modSub(Z1, Z1, t5, curve->p, curve->num_words); /* t3 = B^2 - 2A = x3 */ - uECC_vli_modSub(t5, t5, Z1, curve->p, curve->num_words); /* t5 = A - x3 */ + uECC_vli_modSub(Z1, Z1, t5, curve->p, num_words); /* t3 = B^2 - A */ + uECC_vli_modSub(Z1, Z1, t5, curve->p, num_words); /* t3 = B^2 - 2A = x3 */ + uECC_vli_modSub(t5, t5, Z1, curve->p, num_words); /* t5 = A - x3 */ uECC_vli_modMult_fast(X1, X1, t5, curve); /* t1 = B * (A - x3) */ - uECC_vli_modSub(t4, X1, t4, curve->p, curve->num_words); /* t4 = B * (A - x3) - y1^4 = y3 */ + uECC_vli_modSub(t4, X1, t4, curve->p, num_words); /* t4 = B * (A - x3) - y1^4 = y3 */ - uECC_vli_set(X1, Z1, curve->num_words); - uECC_vli_set(Z1, Y1, curve->num_words); - uECC_vli_set(Y1, t4, curve->num_words); + uECC_vli_set(X1, Z1, num_words); + uECC_vli_set(Z1, Y1, num_words); + uECC_vli_set(Y1, t4, num_words); } #if uECC_SUPPORT_COMPRESSED_POINT @@ -103,28 +104,30 @@ bitcount_t i; uECC_word_t p1[uECC_MAX_WORDS] = {1}; uECC_word_t l_result[uECC_MAX_WORDS] = {1}; + wordcount_t num_words = curve->num_words; /* When curve->p == 3 (mod 4), we can compute sqrt(a) = a^((curve->p + 1) / 4) (mod curve->p). */ - uECC_vli_add(p1, curve->p, p1, curve->num_words); /* p1 = curve_p + 1 */ - for (i = uECC_vli_numBits(p1, curve->num_words) - 1; i > 1; --i) { + uECC_vli_add(p1, curve->p, p1, num_words); /* p1 = curve_p + 1 */ + for (i = uECC_vli_numBits(p1, num_words) - 1; i > 1; --i) { uECC_vli_modSquare_fast(l_result, l_result, curve); if (uECC_vli_testBit(p1, i)) { uECC_vli_modMult_fast(l_result, l_result, a, curve); } } - uECC_vli_set(a, l_result, curve->num_words); + uECC_vli_set(a, l_result, num_words); } #endif /* Computes result = x^3 + ax + b. result must not overlap x. */ static void x_side_default(uECC_word_t *result, const uECC_word_t *x, uECC_Curve curve) { uECC_word_t _3[uECC_MAX_WORDS] = {3}; /* -a = 3 */ + wordcount_t num_words = curve->num_words; uECC_vli_modSquare_fast(result, x, curve); /* r = x^2 */ - uECC_vli_modSub(result, result, _3, curve->p, curve->num_words); /* r = x^2 - 3 */ + uECC_vli_modSub(result, result, _3, curve->p, num_words); /* r = x^2 - 3 */ uECC_vli_modMult_fast(result, result, x, curve); /* r = x^3 - 3x */ - uECC_vli_modAdd(result, result, curve->b, curve->p, curve->num_words); /* r = x^3 - 3x + b */ + uECC_vli_modAdd(result, result, curve->b, curve->p, num_words); /* r = x^3 - 3x + b */ } #if uECC_SUPPORTS_secp160r1
diff --git a/uECC.c b/uECC.c index d5ba7f7..3611a26 100644 --- a/uECC.c +++ b/uECC.c
@@ -613,15 +613,16 @@ const uECC_word_t * const initial_Z, uECC_Curve curve) { uECC_word_t z[uECC_MAX_WORDS]; + wordcount_t num_words = curve->num_words; if (initial_Z) { - uECC_vli_set(z, initial_Z, curve->num_words); + uECC_vli_set(z, initial_Z, num_words); } else { - uECC_vli_clear(z, curve->num_words); + uECC_vli_clear(z, num_words); z[0] = 1; } - uECC_vli_set(X2, X1, curve->num_words); - uECC_vli_set(Y2, Y1, curve->num_words); + uECC_vli_set(X2, X1, num_words); + uECC_vli_set(Y2, Y1, num_words); apply_z(X1, Y1, z, curve); curve->double_jacobian(X1, Y1, z, curve); @@ -639,23 +640,24 @@ uECC_Curve curve) { /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */ uECC_word_t t5[uECC_MAX_WORDS]; + wordcount_t num_words = curve->num_words; - uECC_vli_modSub(t5, X2, X1, curve->p, curve->num_words); /* t5 = x2 - x1 */ + uECC_vli_modSub(t5, X2, X1, curve->p, num_words); /* t5 = x2 - x1 */ uECC_vli_modSquare_fast(t5, t5, curve); /* t5 = (x2 - x1)^2 = A */ uECC_vli_modMult_fast(X1, X1, t5, curve); /* t1 = x1*A = B */ uECC_vli_modMult_fast(X2, X2, t5, curve); /* t3 = x2*A = C */ - uECC_vli_modSub(Y2, Y2, Y1, curve->p, curve->num_words); /* t4 = y2 - y1 */ + uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y2 - y1 */ uECC_vli_modSquare_fast(t5, Y2, curve); /* t5 = (y2 - y1)^2 = D */ - uECC_vli_modSub(t5, t5, X1, curve->p, curve->num_words); /* t5 = D - B */ - uECC_vli_modSub(t5, t5, X2, curve->p, curve->num_words); /* t5 = D - B - C = x3 */ - uECC_vli_modSub(X2, X2, X1, curve->p, curve->num_words); /* t3 = C - B */ + uECC_vli_modSub(t5, t5, X1, curve->p, num_words); /* t5 = D - B */ + uECC_vli_modSub(t5, t5, X2, curve->p, num_words); /* t5 = D - B - C = x3 */ + uECC_vli_modSub(X2, X2, X1, curve->p, num_words); /* t3 = C - B */ uECC_vli_modMult_fast(Y1, Y1, X2, curve); /* t2 = y1*(C - B) */ - uECC_vli_modSub(X2, X1, t5, curve->p, curve->num_words); /* t3 = B - x3 */ + uECC_vli_modSub(X2, X1, t5, curve->p, num_words); /* t3 = B - x3 */ uECC_vli_modMult_fast(Y2, Y2, X2, curve); /* t4 = (y2 - y1)*(B - x3) */ - uECC_vli_modSub(Y2, Y2, Y1, curve->p, curve->num_words); /* t4 = y3 */ + uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y3 */ - uECC_vli_set(X2, t5, curve->num_words); + uECC_vli_set(X2, t5, num_words); } /* Input P = (x1, y1, Z), Q = (x2, y2, Z) @@ -671,31 +673,32 @@ uECC_word_t t5[uECC_MAX_WORDS]; uECC_word_t t6[uECC_MAX_WORDS]; uECC_word_t t7[uECC_MAX_WORDS]; + wordcount_t num_words = curve->num_words; - uECC_vli_modSub(t5, X2, X1, curve->p, curve->num_words); /* t5 = x2 - x1 */ + uECC_vli_modSub(t5, X2, X1, curve->p, num_words); /* t5 = x2 - x1 */ uECC_vli_modSquare_fast(t5, t5, curve); /* t5 = (x2 - x1)^2 = A */ uECC_vli_modMult_fast(X1, X1, t5, curve); /* t1 = x1*A = B */ uECC_vli_modMult_fast(X2, X2, t5, curve); /* t3 = x2*A = C */ - uECC_vli_modAdd(t5, Y2, Y1, curve->p, curve->num_words); /* t5 = y2 + y1 */ - uECC_vli_modSub(Y2, Y2, Y1, curve->p, curve->num_words); /* t4 = y2 - y1 */ + uECC_vli_modAdd(t5, Y2, Y1, curve->p, num_words); /* t5 = y2 + y1 */ + uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = y2 - y1 */ - uECC_vli_modSub(t6, X2, X1, curve->p, curve->num_words); /* t6 = C - B */ + uECC_vli_modSub(t6, X2, X1, curve->p, num_words); /* t6 = C - B */ uECC_vli_modMult_fast(Y1, Y1, t6, curve); /* t2 = y1 * (C - B) = E */ - uECC_vli_modAdd(t6, X1, X2, curve->p, curve->num_words); /* t6 = B + C */ + uECC_vli_modAdd(t6, X1, X2, curve->p, num_words); /* t6 = B + C */ uECC_vli_modSquare_fast(X2, Y2, curve); /* t3 = (y2 - y1)^2 = D */ - uECC_vli_modSub(X2, X2, t6, curve->p, curve->num_words); /* t3 = D - (B + C) = x3 */ + uECC_vli_modSub(X2, X2, t6, curve->p, num_words); /* t3 = D - (B + C) = x3 */ - uECC_vli_modSub(t7, X1, X2, curve->p, curve->num_words); /* t7 = B - x3 */ + uECC_vli_modSub(t7, X1, X2, curve->p, num_words); /* t7 = B - x3 */ uECC_vli_modMult_fast(Y2, Y2, t7, curve); /* t4 = (y2 - y1)*(B - x3) */ - uECC_vli_modSub(Y2, Y2, Y1, curve->p, curve->num_words); /* t4 = (y2 - y1)*(B - x3) - E = y3 */ + uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words); /* t4 = (y2 - y1)*(B - x3) - E = y3 */ uECC_vli_modSquare_fast(t7, t5, curve); /* t7 = (y2 + y1)^2 = F */ - uECC_vli_modSub(t7, t7, t6, curve->p, curve->num_words); /* t7 = F - (B + C) = x3' */ - uECC_vli_modSub(t6, t7, X1, curve->p, curve->num_words); /* t6 = x3' - B */ + uECC_vli_modSub(t7, t7, t6, curve->p, num_words); /* t7 = F - (B + C) = x3' */ + uECC_vli_modSub(t6, t7, X1, curve->p, num_words); /* t6 = x3' - B */ uECC_vli_modMult_fast(t6, t6, t5, curve); /* t6 = (y2+y1)*(x3' - B) */ - uECC_vli_modSub(Y1, t6, Y1, curve->p, curve->num_words); /* t2 = (y2+y1)*(x3' - B) - E = y3' */ + uECC_vli_modSub(Y1, t6, Y1, curve->p, num_words); /* t2 = (y2+y1)*(x3' - B) - E = y3' */ - uECC_vli_set(X1, t7, curve->num_words); + uECC_vli_set(X1, t7, num_words); } /* result may overlap point. */ @@ -711,9 +714,10 @@ uECC_word_t z[uECC_MAX_WORDS]; bitcount_t i; uECC_word_t nb; + wordcount_t num_words = curve->num_words; - uECC_vli_set(Rx[1], point, curve->num_words); - uECC_vli_set(Ry[1], point + curve->num_words, curve->num_words); + uECC_vli_set(Rx[1], point, num_words); + uECC_vli_set(Ry[1], point + num_words, num_words); XYcZ_initial_double(Rx[1], Ry[1], Rx[0], Ry[0], initial_Z, curve); @@ -727,31 +731,32 @@ XYcZ_addC(Rx[1 - nb], Ry[1 - nb], Rx[nb], Ry[nb], curve); /* Find final 1/Z value. */ - uECC_vli_modSub(z, Rx[1], Rx[0], curve->p, curve->num_words); /* X1 - X0 */ + uECC_vli_modSub(z, Rx[1], Rx[0], curve->p, num_words); /* X1 - X0 */ uECC_vli_modMult_fast(z, z, Ry[1 - nb], curve); /* Yb * (X1 - X0) */ uECC_vli_modMult_fast(z, z, point, curve); /* xP * Yb * (X1 - X0) */ - uECC_vli_modInv(z, z, curve->p, curve->num_words); /* 1 / (xP * Yb * (X1 - X0)) */ + uECC_vli_modInv(z, z, curve->p, num_words); /* 1 / (xP * Yb * (X1 - X0)) */ /* yP / (xP * Yb * (X1 - X0)) */ - uECC_vli_modMult_fast(z, z, point + curve->num_words, curve); + uECC_vli_modMult_fast(z, z, point + num_words, curve); uECC_vli_modMult_fast(z, z, Rx[1 - nb], curve); /* Xb * yP / (xP * Yb * (X1 - X0)) */ /* End 1/Z calculation */ XYcZ_add(Rx[nb], Ry[nb], Rx[1 - nb], Ry[1 - nb], curve); apply_z(Rx[0], Ry[0], z, curve); - uECC_vli_set(result, Rx[0], curve->num_words); - uECC_vli_set(result + curve->num_words, Ry[0], curve->num_words); + uECC_vli_set(result, Rx[0], num_words); + uECC_vli_set(result + num_words, Ry[0], num_words); } static uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0, uECC_word_t *k1, uECC_Curve curve) { - bitcount_t num_bits = uECC_vli_numBits(curve->n, curve->num_n_words); - uECC_word_t carry = uECC_vli_add(k0, k, curve->n, curve->num_n_words) || - (num_bits < ((bitcount_t)curve->num_n_words * uECC_WORD_SIZE * 8) && + wordcount_t num_n_words = curve->num_n_words; + bitcount_t num_bits = uECC_vli_numBits(curve->n, num_n_words); + uECC_word_t carry = uECC_vli_add(k0, k, curve->n, num_n_words) || + (num_bits < ((bitcount_t)num_n_words * uECC_WORD_SIZE * 8) && uECC_vli_testBit(k0, num_bits)); - uECC_vli_add(k1, k0, curve->n, curve->num_n_words); + uECC_vli_add(k1, k0, curve->n, num_n_words); return carry; } @@ -790,8 +795,9 @@ uECC_VLI_API void uECC_vli_nativeToBytes(uint8_t *bytes, const uint8_t *native, uECC_Curve curve) { wordcount_t i; - for (i = 0; i < curve->num_words; ++i) { - dest[i] = src[(curve->num_words - 1) - i]; + wordcount_t num_words = curve->num_words; + for (i = 0; i < num_words; ++i) { + dest[i] = src[(num_words - 1) - i]; } } @@ -803,8 +809,9 @@ uECC_VLI_API void uECC_vli_nativeToBytes(uint8_t *bytes, const uint32_t *native, uECC_Curve curve) { wordcount_t i; - for (i = 0; i < curve->num_words; ++i) { - uint8_t *digit = bytes + 4 * (curve->num_words - 1 - i); + wordcount_t num_words = curve->num_words; + for (i = 0; i < num_words; ++i) { + uint8_t *digit = bytes + 4 * (num_words - 1 - i); digit[0] = native[i] >> 24; digit[1] = native[i] >> 16; digit[2] = native[i] >> 8; @@ -814,8 +821,9 @@ uECC_VLI_API void uECC_vli_bytesToNative(uint32_t *native, const uint8_t *bytes, uECC_Curve curve) { wordcount_t i; - for (i = 0; i < curve->num_words; ++i) { - const uint8_t *digit = bytes + 4 * (curve->num_words - 1 - i); + wordcount_t num_words = curve->num_words; + for (i = 0; i < num_words; ++i) { + const uint8_t *digit = bytes + 4 * (num_words - 1 - i); native[i] = ((uint32_t)digit[0] << 24) | ((uint32_t)digit[1] << 16) | ((uint32_t)digit[2] << 8) | (uint32_t)digit[3]; } @@ -825,17 +833,19 @@ uECC_VLI_API void uECC_vli_nativeToBytes(uint8_t *bytes, const uint64_t *native, uECC_Curve curve) { wordcount_t i; - for (i = 0; i < curve->num_bytes; ++i) { - unsigned b = curve->num_bytes - 1 - i; + wordcount_t num_bytes = curve->num_bytes; + for (i = 0; i < num_bytes; ++i) { + unsigned b = num_bytes - 1 - i; bytes[i] = native[b / 8] >> (8 * (b % 8)); } } uECC_VLI_API void uECC_vli_bytesToNative(uint64_t *native, const uint8_t *bytes, uECC_Curve curve) { wordcount_t i; + wordcount_t num_bytes = curve->num_bytes; uECC_vli_clear(native, curve->num_words); - for (i = 0; i < curve->num_bytes; ++i) { - unsigned b = curve->num_bytes - 1 - i; + for (i = 0; i < num_bytes; ++i) { + unsigned b = num_bytes - 1 - i; native[b / 8] |= (uint64_t)bytes[i] << (8 * (b % 8)); } } @@ -846,12 +856,12 @@ in the buffer (if any) are zeroed. */ static cmpresult_t generate_random_int(uECC_word_t *random, wordcount_t num_words, - const wordcount_t num_bits) { + wordcount_t num_bits) { if (!g_rng_function || !g_rng_function((uint8_t *)random, num_words * uECC_WORD_SIZE)) { return 0; } if (num_words * uECC_WORD_SIZE * 8 > num_bits) { - wordcount_t mask = (wordcount_t)-1; + uECC_word_t mask = (uECC_word_t)-1; random[num_words - 1] &= mask >> ((bitcount_t)(num_words * uECC_WORD_SIZE * 8 - num_bits)); } return 1; @@ -893,13 +903,14 @@ uECC_word_t *initial_Z = 0; uECC_word_t tries; uECC_word_t carry; + wordcount_t num_words = curve->num_words; /* Zero out correctly (for addition with curve->n) for secp160r1. */ private[curve->num_n_words - 1] = 0; uECC_vli_bytesToNative(private, private_key, curve); uECC_vli_bytesToNative(public, public_key, curve); - uECC_vli_bytesToNative(public + curve->num_words, public_key + curve->num_bytes, curve); + uECC_vli_bytesToNative(public + num_words, public_key + curve->num_bytes, curve); /* Regularize the bitcount for the private key so that attackers cannot use a side channel attack to learn the number of leading zeros. */ @@ -909,12 +920,12 @@ protection against side-channel attacks. */ if (g_rng_function) { for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) { - if (!generate_random_int(p2[carry], curve->num_words, curve->num_bytes * 8)) { + if (!generate_random_int(p2[carry], num_words, curve->num_bytes * 8)) { return 0; } - if (!uECC_vli_isZero(p2[carry], curve->num_words) && - uECC_vli_cmp(curve->p, p2[carry], curve->num_words) == 1) { + if (!uECC_vli_isZero(p2[carry], num_words) && + uECC_vli_cmp(curve->p, p2[carry], num_words) == 1) { initial_Z = p2[carry]; break; } @@ -956,6 +967,7 @@ int uECC_valid_point(const uECC_word_t *point, uECC_Curve curve) { uECC_word_t tmp1[uECC_MAX_WORDS]; uECC_word_t tmp2[uECC_MAX_WORDS]; + wordcount_t num_words = curve->num_words; /* The point at infinity is invalid. */ if (EccPoint_isZero(point, curve)) { @@ -963,16 +975,16 @@ } /* x and y must be smaller than p. */ - if (uECC_vli_cmp(curve->p, point, curve->num_words) != 1 || - uECC_vli_cmp(curve->p, point + curve->num_words, curve->num_words) != 1) { + if (uECC_vli_cmp(curve->p, point, num_words) != 1 || + uECC_vli_cmp(curve->p, point + num_words, num_words) != 1) { return 0; } - uECC_vli_modSquare_fast(tmp1, point + curve->num_words, curve); + uECC_vli_modSquare_fast(tmp1, point + num_words, curve); curve->x_side(tmp2, point, curve); /* tmp2 = x^3 + ax + b */ /* Make sure that y^2 == x^3 + ax + b */ - return (uECC_vli_equal(tmp1, tmp2, curve->num_words)); + return (uECC_vli_equal(tmp1, tmp2, num_words)); } int uECC_valid_public_key(const uint8_t *public_key, uECC_Curve curve) { @@ -1011,33 +1023,34 @@ uECC_word_t *k2[2] = {tmp, s}; uECC_word_t p[uECC_MAX_WORDS * 2]; uECC_word_t carry; - bitcount_t num_n_bits = uECC_vli_numBits(curve->n, curve->num_n_words); + wordcount_t num_words = curve->num_words; + wordcount_t num_n_words = curve->num_n_words; + bitcount_t num_n_bits = uECC_vli_numBits(curve->n, num_n_words); /* Make sure 0 < k < curve_n */ - if (uECC_vli_isZero(k, curve->num_words) || - uECC_vli_cmp(curve->n, k, curve->num_n_words) != 1) { + if (uECC_vli_isZero(k, num_words) || uECC_vli_cmp(curve->n, k, num_n_words) != 1) { return 0; } carry = regularize_k(k, tmp, s, curve); EccPoint_mult(p, curve->G, k2[!carry], 0, num_n_bits + 1, curve); - if (uECC_vli_isZero(p, curve->num_words)) { + if (uECC_vli_isZero(p, num_words)) { return 0; } /* Attempt to get a random number to prevent side channel analysis of k. */ if (!g_rng_function) { - uECC_vli_clear(tmp, curve->num_n_words); + uECC_vli_clear(tmp, num_n_words); tmp[0] = 1; } else { uECC_word_t tries; for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) { - if (!generate_random_int(tmp, curve->num_n_words, num_n_bits)) { + if (!generate_random_int(tmp, num_n_words, num_n_bits)) { return 0; } - if (!uECC_vli_isZero(tmp, curve->num_n_words) && - uECC_vli_cmp(curve->n, tmp, curve->num_n_words) == 1) { + if (!uECC_vli_isZero(tmp, num_n_words) && + uECC_vli_cmp(curve->n, tmp, num_n_words) == 1) { goto got_random; } } @@ -1046,22 +1059,22 @@ got_random: /* Prevent side channel analysis of uECC_vli_modInv() to determine bits of k / the private key by premultiplying by a random number */ - uECC_vli_modMult(k, k, tmp, curve->n, curve->num_n_words); /* k' = rand * k */ - uECC_vli_modInv(k, k, curve->n, curve->num_n_words); /* k = 1 / k' */ - uECC_vli_modMult(k, k, tmp, curve->n, curve->num_n_words); /* k = 1 / k */ + uECC_vli_modMult(k, k, tmp, curve->n, num_n_words); /* k' = rand * k */ + uECC_vli_modInv(k, k, curve->n, num_n_words); /* k = 1 / k' */ + uECC_vli_modMult(k, k, tmp, curve->n, num_n_words); /* k = 1 / k */ uECC_vli_nativeToBytes(signature, p, curve); /* store r */ - tmp[curve->num_n_words - 1] = 0; + tmp[num_n_words - 1] = 0; uECC_vli_bytesToNative(tmp, private_key, curve); /* tmp = d */ - s[curve->num_n_words - 1] = 0; - uECC_vli_set(s, p, curve->num_words); - uECC_vli_modMult(s, tmp, s, curve->n, curve->num_n_words); /* s = r*d */ + s[num_n_words - 1] = 0; + uECC_vli_set(s, p, num_words); + uECC_vli_modMult(s, tmp, s, curve->n, num_n_words); /* s = r*d */ uECC_vli_bytesToNative(tmp, message_hash, curve); - uECC_vli_modAdd(s, tmp, s, curve->n, curve->num_n_words); /* s = e + r*d */ - uECC_vli_modMult(s, s, k, curve->n, curve->num_n_words); /* s = (e + r*d) / k */ - if (uECC_vli_numBits(s, curve->num_n_words) > (bitcount_t)curve->num_bytes * 8) { + uECC_vli_modAdd(s, tmp, s, curve->n, num_n_words); /* s = e + r*d */ + uECC_vli_modMult(s, s, k, curve->n, num_n_words); /* s = (e + r*d) / k */ + if (uECC_vli_numBits(s, num_n_words) > (bitcount_t)curve->num_bytes * 8) { return 0; } uECC_vli_nativeToBytes(signature + curve->num_bytes, s, curve); @@ -1144,7 +1157,9 @@ uECC_Curve curve) { uint8_t *K = hash_context->tmp; uint8_t *V = K + hash_context->result_size; - bitcount_t num_n_bits = uECC_vli_numBits(curve->n, curve->num_n_words); + wordcount_t num_bytes = curve->num_bytes; + wordcount_t num_n_words = curve->num_n_words; + bitcount_t num_n_bits = uECC_vli_numBits(curve->n, num_n_words); uECC_word_t tries; unsigned i; for (i = 0; i < hash_context->result_size; ++i) { @@ -1156,8 +1171,8 @@ HMAC_init(hash_context, K); V[hash_context->result_size] = 0x00; HMAC_update(hash_context, V, hash_context->result_size + 1); - HMAC_update(hash_context, private_key, curve->num_bytes); - HMAC_update(hash_context, message_hash, curve->num_bytes); + HMAC_update(hash_context, private_key, num_bytes); + HMAC_update(hash_context, message_hash, num_bytes); HMAC_finish(hash_context, K, K); update_V(hash_context, K, V); @@ -1166,8 +1181,8 @@ HMAC_init(hash_context, K); V[hash_context->result_size] = 0x01; HMAC_update(hash_context, V, hash_context->result_size + 1); - HMAC_update(hash_context, private_key, curve->num_bytes); - HMAC_update(hash_context, message_hash, curve->num_bytes); + HMAC_update(hash_context, private_key, num_bytes); + HMAC_update(hash_context, message_hash, num_bytes); HMAC_finish(hash_context, K, K); update_V(hash_context, K, V); @@ -1180,16 +1195,16 @@ update_V(hash_context, K, V); for (i = 0; i < hash_context->result_size; ++i) { T_ptr[T_bytes++] = V[i]; - if (T_bytes >= curve->num_n_words * uECC_WORD_SIZE) { + if (T_bytes >= num_n_words * uECC_WORD_SIZE) { goto filled; } } } filled: - if ((bitcount_t)curve->num_n_words * uECC_WORD_SIZE * 8 > num_n_bits) { - wordcount_t mask = (wordcount_t)-1; - T[curve->num_n_words - 1] &= - mask >> ((bitcount_t)(curve->num_n_words * uECC_WORD_SIZE * 8 - num_n_bits)); + if ((bitcount_t)num_n_words * uECC_WORD_SIZE * 8 > num_n_bits) { + uECC_word_t mask = (uECC_word_t)-1; + T[num_n_words - 1] &= + mask >> ((bitcount_t)(num_n_words * uECC_WORD_SIZE * 8 - num_n_bits)); } if (uECC_sign_with_k(private_key, message_hash, T, signature, curve)) { @@ -1229,58 +1244,59 @@ bitcount_t num_bits; bitcount_t i; uECC_word_t r[uECC_MAX_WORDS], s[uECC_MAX_WORDS]; + wordcount_t num_words = curve->num_words; + wordcount_t num_n_words = curve->num_n_words; - - rx[curve->num_n_words - 1] = 0; - r[curve->num_n_words - 1] = 0; - s[curve->num_n_words - 1] = 0; + rx[num_n_words - 1] = 0; + r[num_n_words - 1] = 0; + s[num_n_words - 1] = 0; uECC_vli_bytesToNative(public, public_key, curve); - uECC_vli_bytesToNative(public + curve->num_words, public_key + curve->num_bytes, curve); + uECC_vli_bytesToNative(public + num_words, public_key + curve->num_bytes, curve); uECC_vli_bytesToNative(r, signature, curve); uECC_vli_bytesToNative(s, signature + curve->num_bytes, curve); /* r, s must not be 0. */ - if (uECC_vli_isZero(r, curve->num_words) || uECC_vli_isZero(s, curve->num_words)) { + if (uECC_vli_isZero(r, num_words) || uECC_vli_isZero(s, num_words)) { return 0; } /* r, s must be < n. */ - if (uECC_vli_cmp(curve->n, r, curve->num_n_words) != 1 || - uECC_vli_cmp(curve->n, s, curve->num_n_words) != 1) { + if (uECC_vli_cmp(curve->n, r, num_n_words) != 1 || + uECC_vli_cmp(curve->n, s, num_n_words) != 1) { return 0; } /* Calculate u1 and u2. */ - uECC_vli_modInv(z, s, curve->n, curve->num_n_words); /* z = 1/s */ - u1[curve->num_n_words - 1] = 0; + uECC_vli_modInv(z, s, curve->n, num_n_words); /* z = 1/s */ + u1[num_n_words - 1] = 0; uECC_vli_bytesToNative(u1, hash, curve); - uECC_vli_modMult(u1, u1, z, curve->n, curve->num_n_words); /* u1 = e/s */ - uECC_vli_modMult(u2, r, z, curve->n, curve->num_n_words); /* u2 = r/s */ + uECC_vli_modMult(u1, u1, z, curve->n, num_n_words); /* u1 = e/s */ + uECC_vli_modMult(u2, r, z, curve->n, num_n_words); /* u2 = r/s */ /* Calculate sum = G + Q. */ - uECC_vli_set(sum, public, curve->num_words); - uECC_vli_set(sum + curve->num_words, public + curve->num_words, curve->num_words); - uECC_vli_set(tx, curve->G, curve->num_words); - uECC_vli_set(ty, curve->G + curve->num_words, curve->num_words); - uECC_vli_modSub(z, sum, tx, curve->p, curve->num_words); /* z = x2 - x1 */ - XYcZ_add(tx, ty, sum, sum + curve->num_words, curve); - uECC_vli_modInv(z, z, curve->p, curve->num_words); /* z = 1/z */ - apply_z(sum, sum + curve->num_words, z, curve); + uECC_vli_set(sum, public, num_words); + uECC_vli_set(sum + num_words, public + num_words, num_words); + uECC_vli_set(tx, curve->G, num_words); + uECC_vli_set(ty, curve->G + num_words, num_words); + uECC_vli_modSub(z, sum, tx, curve->p, num_words); /* z = x2 - x1 */ + XYcZ_add(tx, ty, sum, sum + num_words, curve); + uECC_vli_modInv(z, z, curve->p, num_words); /* z = 1/z */ + apply_z(sum, sum + num_words, z, curve); /* Use Shamir's trick to calculate u1*G + u2*Q */ points[0] = 0; points[1] = curve->G; points[2] = public; points[3] = sum; - num_bits = smax(uECC_vli_numBits(u1, curve->num_n_words), - uECC_vli_numBits(u2, curve->num_n_words)); + num_bits = smax(uECC_vli_numBits(u1, num_n_words), + uECC_vli_numBits(u2, num_n_words)); point = points[(!!uECC_vli_testBit(u1, num_bits - 1)) | ((!!uECC_vli_testBit(u2, num_bits - 1)) << 1)]; - uECC_vli_set(rx, point, curve->num_words); - uECC_vli_set(ry, point + curve->num_words, curve->num_words); - uECC_vli_clear(z, curve->num_words); + uECC_vli_set(rx, point, num_words); + uECC_vli_set(ry, point + num_words, num_words); + uECC_vli_clear(z, num_words); z[0] = 1; for (i = num_bits - 2; i >= 0; --i) { @@ -1290,25 +1306,25 @@ index = (!!uECC_vli_testBit(u1, i)) | ((!!uECC_vli_testBit(u2, i)) << 1); point = points[index]; if (point) { - uECC_vli_set(tx, point, curve->num_words); - uECC_vli_set(ty, point + curve->num_words, curve->num_words); + uECC_vli_set(tx, point, num_words); + uECC_vli_set(ty, point + num_words, num_words); apply_z(tx, ty, z, curve); - uECC_vli_modSub(tz, rx, tx, curve->p, curve->num_words); /* Z = x2 - x1 */ + uECC_vli_modSub(tz, rx, tx, curve->p, num_words); /* Z = x2 - x1 */ XYcZ_add(tx, ty, rx, ry, curve); uECC_vli_modMult_fast(z, z, tz, curve); } } - uECC_vli_modInv(z, z, curve->p, curve->num_words); /* Z = 1/Z */ + uECC_vli_modInv(z, z, curve->p, num_words); /* Z = 1/Z */ apply_z(rx, ry, z, curve); /* v = x1 (mod n) */ - if (uECC_vli_cmp(curve->n, rx, curve->num_n_words) != 1) { - uECC_vli_sub(rx, rx, curve->n, curve->num_n_words); + if (uECC_vli_cmp(curve->n, rx, num_n_words) != 1) { + uECC_vli_sub(rx, rx, curve->n, num_n_words); } /* Accept only if v == r. */ - return (uECC_vli_equal(rx, r, curve->num_words)); + return (uECC_vli_equal(rx, r, num_words)); } #if uECC_ENABLE_VLI_API