Add micro-ecc based ecc-files to mbedtls
The files are from https://github.com/intel/tinycrypt
Using commit 6e0eb53fc8403988f97345e94081b0453f47231d as a base.
diff --git a/tinycrypt/ecc.c b/tinycrypt/ecc.c
new file mode 100644
index 0000000..46080bf
--- /dev/null
+++ b/tinycrypt/ecc.c
@@ -0,0 +1,942 @@
+/* ecc.c - TinyCrypt implementation of common ECC functions */
+
+/*
+ * Copyright (c) 2014, Kenneth MacKay
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Copyright (C) 2017 by Intel Corporation, All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of Intel Corporation nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <tinycrypt/ecc.h>
+#include <tinycrypt/ecc_platform_specific.h>
+#include <string.h>
+
+/* IMPORTANT: Make sure a cryptographically-secure PRNG is set and the platform
+ * has access to enough entropy in order to feed the PRNG regularly. */
+#if default_RNG_defined
+static uECC_RNG_Function g_rng_function = &default_CSPRNG;
+#else
+static uECC_RNG_Function g_rng_function = 0;
+#endif
+
+void uECC_set_rng(uECC_RNG_Function rng_function)
+{
+ g_rng_function = rng_function;
+}
+
+uECC_RNG_Function uECC_get_rng(void)
+{
+ return g_rng_function;
+}
+
+int uECC_curve_private_key_size(uECC_Curve curve)
+{
+ return BITS_TO_BYTES(curve->num_n_bits);
+}
+
+int uECC_curve_public_key_size(uECC_Curve curve)
+{
+ return 2 * curve->num_bytes;
+}
+
+void uECC_vli_clear(uECC_word_t *vli, wordcount_t num_words)
+{
+ wordcount_t i;
+ for (i = 0; i < num_words; ++i) {
+ vli[i] = 0;
+ }
+}
+
+uECC_word_t uECC_vli_isZero(const uECC_word_t *vli, wordcount_t num_words)
+{
+ uECC_word_t bits = 0;
+ wordcount_t i;
+ for (i = 0; i < num_words; ++i) {
+ bits |= vli[i];
+ }
+ return (bits == 0);
+}
+
+uECC_word_t uECC_vli_testBit(const uECC_word_t *vli, bitcount_t bit)
+{
+ return (vli[bit >> uECC_WORD_BITS_SHIFT] &
+ ((uECC_word_t)1 << (bit & uECC_WORD_BITS_MASK)));
+}
+
+/* Counts the number of words in vli. */
+static wordcount_t vli_numDigits(const uECC_word_t *vli,
+ const wordcount_t max_words)
+{
+
+ wordcount_t i;
+ /* Search from the end until we find a non-zero digit. We do it in reverse
+ * because we expect that most digits will be nonzero. */
+ for (i = max_words - 1; i >= 0 && vli[i] == 0; --i) {
+ }
+
+ return (i + 1);
+}
+
+bitcount_t uECC_vli_numBits(const uECC_word_t *vli,
+ const wordcount_t max_words)
+{
+
+ uECC_word_t i;
+ uECC_word_t digit;
+
+ wordcount_t num_digits = vli_numDigits(vli, max_words);
+ if (num_digits == 0) {
+ return 0;
+ }
+
+ digit = vli[num_digits - 1];
+ for (i = 0; digit; ++i) {
+ digit >>= 1;
+ }
+
+ return (((bitcount_t)(num_digits - 1) << uECC_WORD_BITS_SHIFT) + i);
+}
+
+void uECC_vli_set(uECC_word_t *dest, const uECC_word_t *src,
+ wordcount_t num_words)
+{
+ wordcount_t i;
+
+ for (i = 0; i < num_words; ++i) {
+ dest[i] = src[i];
+ }
+}
+
+cmpresult_t uECC_vli_cmp_unsafe(const uECC_word_t *left,
+ const uECC_word_t *right,
+ wordcount_t num_words)
+{
+ wordcount_t i;
+
+ for (i = num_words - 1; i >= 0; --i) {
+ if (left[i] > right[i]) {
+ return 1;
+ } else if (left[i] < right[i]) {
+ return -1;
+ }
+ }
+ return 0;
+}
+
+uECC_word_t uECC_vli_equal(const uECC_word_t *left, const uECC_word_t *right,
+ wordcount_t num_words)
+{
+
+ uECC_word_t diff = 0;
+ wordcount_t i;
+
+ for (i = num_words - 1; i >= 0; --i) {
+ diff |= (left[i] ^ right[i]);
+ }
+ return !(diff == 0);
+}
+
+uECC_word_t cond_set(uECC_word_t p_true, uECC_word_t p_false, unsigned int cond)
+{
+ return (p_true*(cond)) | (p_false*(!cond));
+}
+
+/* Computes result = left - right, returning borrow, in constant time.
+ * Can modify in place. */
+uECC_word_t uECC_vli_sub(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, wordcount_t num_words)
+{
+ uECC_word_t borrow = 0;
+ wordcount_t i;
+ for (i = 0; i < num_words; ++i) {
+ uECC_word_t diff = left[i] - right[i] - borrow;
+ uECC_word_t val = (diff > left[i]);
+ borrow = cond_set(val, borrow, (diff != left[i]));
+
+ result[i] = diff;
+ }
+ return borrow;
+}
+
+/* Computes result = left + right, returning carry, in constant time.
+ * Can modify in place. */
+static uECC_word_t uECC_vli_add(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, wordcount_t num_words)
+{
+ uECC_word_t carry = 0;
+ wordcount_t i;
+ for (i = 0; i < num_words; ++i) {
+ uECC_word_t sum = left[i] + right[i] + carry;
+ uECC_word_t val = (sum < left[i]);
+ carry = cond_set(val, carry, (sum != left[i]));
+ result[i] = sum;
+ }
+ return carry;
+}
+
+cmpresult_t uECC_vli_cmp(const uECC_word_t *left, const uECC_word_t *right,
+ wordcount_t num_words)
+{
+ uECC_word_t tmp[NUM_ECC_WORDS];
+ uECC_word_t neg = !!uECC_vli_sub(tmp, left, right, num_words);
+ uECC_word_t equal = uECC_vli_isZero(tmp, num_words);
+ return (!equal - 2 * neg);
+}
+
+/* Computes vli = vli >> 1. */
+static void uECC_vli_rshift1(uECC_word_t *vli, wordcount_t num_words)
+{
+ uECC_word_t *end = vli;
+ uECC_word_t carry = 0;
+
+ vli += num_words;
+ while (vli-- > end) {
+ uECC_word_t temp = *vli;
+ *vli = (temp >> 1) | carry;
+ carry = temp << (uECC_WORD_BITS - 1);
+ }
+}
+
+static void muladd(uECC_word_t a, uECC_word_t b, uECC_word_t *r0,
+ uECC_word_t *r1, uECC_word_t *r2)
+{
+
+ uECC_dword_t p = (uECC_dword_t)a * b;
+ uECC_dword_t r01 = ((uECC_dword_t)(*r1) << uECC_WORD_BITS) | *r0;
+ r01 += p;
+ *r2 += (r01 < p);
+ *r1 = r01 >> uECC_WORD_BITS;
+ *r0 = (uECC_word_t)r01;
+
+}
+
+/* Computes result = left * right. Result must be 2 * num_words long. */
+static void uECC_vli_mult(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, wordcount_t num_words)
+{
+
+ uECC_word_t r0 = 0;
+ uECC_word_t r1 = 0;
+ uECC_word_t r2 = 0;
+ wordcount_t i, k;
+
+ /* Compute each digit of result in sequence, maintaining the carries. */
+ for (k = 0; k < num_words; ++k) {
+
+ for (i = 0; i <= k; ++i) {
+ muladd(left[i], right[k - i], &r0, &r1, &r2);
+ }
+
+ result[k] = r0;
+ r0 = r1;
+ r1 = r2;
+ r2 = 0;
+ }
+
+ for (k = num_words; k < num_words * 2 - 1; ++k) {
+
+ for (i = (k + 1) - num_words; i < num_words; ++i) {
+ muladd(left[i], right[k - i], &r0, &r1, &r2);
+ }
+ result[k] = r0;
+ r0 = r1;
+ r1 = r2;
+ r2 = 0;
+ }
+ result[num_words * 2 - 1] = r0;
+}
+
+void uECC_vli_modAdd(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, const uECC_word_t *mod,
+ wordcount_t num_words)
+{
+ uECC_word_t carry = uECC_vli_add(result, left, right, num_words);
+ if (carry || uECC_vli_cmp_unsafe(mod, result, num_words) != 1) {
+ /* result > mod (result = mod + remainder), so subtract mod to get
+ * remainder. */
+ uECC_vli_sub(result, result, mod, num_words);
+ }
+}
+
+void uECC_vli_modSub(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, const uECC_word_t *mod,
+ wordcount_t num_words)
+{
+ uECC_word_t l_borrow = uECC_vli_sub(result, left, right, num_words);
+ if (l_borrow) {
+ /* In this case, result == -diff == (max int) - diff. Since -x % d == d - x,
+ * we can get the correct result from result + mod (with overflow). */
+ uECC_vli_add(result, result, mod, num_words);
+ }
+}
+
+/* Computes result = product % mod, where product is 2N words long. */
+/* Currently only designed to work for curve_p or curve_n. */
+void uECC_vli_mmod(uECC_word_t *result, uECC_word_t *product,
+ const uECC_word_t *mod, wordcount_t num_words)
+{
+ uECC_word_t mod_multiple[2 * NUM_ECC_WORDS];
+ uECC_word_t tmp[2 * NUM_ECC_WORDS];
+ uECC_word_t *v[2] = {tmp, product};
+ uECC_word_t index;
+
+ /* Shift mod so its highest set bit is at the maximum position. */
+ bitcount_t shift = (num_words * 2 * uECC_WORD_BITS) -
+ uECC_vli_numBits(mod, num_words);
+ wordcount_t word_shift = shift / uECC_WORD_BITS;
+ wordcount_t bit_shift = shift % uECC_WORD_BITS;
+ uECC_word_t carry = 0;
+ uECC_vli_clear(mod_multiple, word_shift);
+ if (bit_shift > 0) {
+ for(index = 0; index < (uECC_word_t)num_words; ++index) {
+ mod_multiple[word_shift + index] = (mod[index] << bit_shift) | carry;
+ carry = mod[index] >> (uECC_WORD_BITS - bit_shift);
+ }
+ } else {
+ uECC_vli_set(mod_multiple + word_shift, mod, num_words);
+ }
+
+ for (index = 1; shift >= 0; --shift) {
+ uECC_word_t borrow = 0;
+ wordcount_t i;
+ for (i = 0; i < num_words * 2; ++i) {
+ uECC_word_t diff = v[index][i] - mod_multiple[i] - borrow;
+ if (diff != v[index][i]) {
+ borrow = (diff > v[index][i]);
+ }
+ v[1 - index][i] = diff;
+ }
+ /* Swap the index if there was no borrow */
+ index = !(index ^ borrow);
+ uECC_vli_rshift1(mod_multiple, num_words);
+ mod_multiple[num_words - 1] |= mod_multiple[num_words] <<
+ (uECC_WORD_BITS - 1);
+ uECC_vli_rshift1(mod_multiple + num_words, num_words);
+ }
+ uECC_vli_set(result, v[index], num_words);
+}
+
+void uECC_vli_modMult(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, const uECC_word_t *mod,
+ wordcount_t num_words)
+{
+ uECC_word_t product[2 * NUM_ECC_WORDS];
+ uECC_vli_mult(product, left, right, num_words);
+ uECC_vli_mmod(result, product, mod, num_words);
+}
+
+void uECC_vli_modMult_fast(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, uECC_Curve curve)
+{
+ uECC_word_t product[2 * NUM_ECC_WORDS];
+ uECC_vli_mult(product, left, right, curve->num_words);
+
+ curve->mmod_fast(result, product);
+}
+
+static void uECC_vli_modSquare_fast(uECC_word_t *result,
+ const uECC_word_t *left,
+ uECC_Curve curve)
+{
+ uECC_vli_modMult_fast(result, left, left, curve);
+}
+
+
+#define EVEN(vli) (!(vli[0] & 1))
+
+static void vli_modInv_update(uECC_word_t *uv,
+ const uECC_word_t *mod,
+ wordcount_t num_words)
+{
+
+ uECC_word_t carry = 0;
+
+ if (!EVEN(uv)) {
+ carry = uECC_vli_add(uv, uv, mod, num_words);
+ }
+ uECC_vli_rshift1(uv, num_words);
+ if (carry) {
+ uv[num_words - 1] |= HIGH_BIT_SET;
+ }
+}
+
+void uECC_vli_modInv(uECC_word_t *result, const uECC_word_t *input,
+ const uECC_word_t *mod, wordcount_t num_words)
+{
+ uECC_word_t a[NUM_ECC_WORDS], b[NUM_ECC_WORDS];
+ uECC_word_t u[NUM_ECC_WORDS], v[NUM_ECC_WORDS];
+ cmpresult_t cmpResult;
+
+ if (uECC_vli_isZero(input, num_words)) {
+ uECC_vli_clear(result, num_words);
+ return;
+ }
+
+ uECC_vli_set(a, input, num_words);
+ uECC_vli_set(b, mod, num_words);
+ uECC_vli_clear(u, num_words);
+ u[0] = 1;
+ uECC_vli_clear(v, num_words);
+ while ((cmpResult = uECC_vli_cmp_unsafe(a, b, num_words)) != 0) {
+ if (EVEN(a)) {
+ uECC_vli_rshift1(a, num_words);
+ vli_modInv_update(u, mod, num_words);
+ } else if (EVEN(b)) {
+ uECC_vli_rshift1(b, num_words);
+ vli_modInv_update(v, mod, num_words);
+ } else if (cmpResult > 0) {
+ uECC_vli_sub(a, a, b, num_words);
+ uECC_vli_rshift1(a, num_words);
+ if (uECC_vli_cmp_unsafe(u, v, num_words) < 0) {
+ uECC_vli_add(u, u, mod, num_words);
+ }
+ uECC_vli_sub(u, u, v, num_words);
+ vli_modInv_update(u, mod, num_words);
+ } else {
+ uECC_vli_sub(b, b, a, num_words);
+ uECC_vli_rshift1(b, num_words);
+ if (uECC_vli_cmp_unsafe(v, u, num_words) < 0) {
+ uECC_vli_add(v, v, mod, num_words);
+ }
+ uECC_vli_sub(v, v, u, num_words);
+ vli_modInv_update(v, mod, num_words);
+ }
+ }
+ uECC_vli_set(result, u, num_words);
+}
+
+/* ------ Point operations ------ */
+
+void double_jacobian_default(uECC_word_t * X1, uECC_word_t * Y1,
+ uECC_word_t * Z1, uECC_Curve curve)
+{
+ /* t1 = X, t2 = Y, t3 = Z */
+ uECC_word_t t4[NUM_ECC_WORDS];
+ uECC_word_t t5[NUM_ECC_WORDS];
+ wordcount_t num_words = curve->num_words;
+
+ if (uECC_vli_isZero(Z1, num_words)) {
+ return;
+ }
+
+ uECC_vli_modSquare_fast(t4, Y1, curve); /* t4 = y1^2 */
+ uECC_vli_modMult_fast(t5, X1, t4, curve); /* t5 = x1*y1^2 = A */
+ uECC_vli_modSquare_fast(t4, t4, curve); /* t4 = y1^4 */
+ 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, 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, 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, num_words);
+ uECC_vli_rshift1(X1, num_words);
+ X1[num_words - 1] |= l_carry << (uECC_WORD_BITS - 1);
+ } else {
+ 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, 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) */
+ /* t4 = B * (A - x3) - y1^4 = y3: */
+ uECC_vli_modSub(t4, X1, t4, curve->p, num_words);
+
+ uECC_vli_set(X1, Z1, num_words);
+ uECC_vli_set(Z1, Y1, num_words);
+ uECC_vli_set(Y1, t4, num_words);
+}
+
+void x_side_default(uECC_word_t *result,
+ const uECC_word_t *x,
+ uECC_Curve curve)
+{
+ uECC_word_t _3[NUM_ECC_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, num_words); /* r = x^2 - 3 */
+ uECC_vli_modMult_fast(result, result, x, curve); /* r = x^3 - 3x */
+ /* r = x^3 - 3x + b: */
+ uECC_vli_modAdd(result, result, curve->b, curve->p, num_words);
+}
+
+uECC_Curve uECC_secp256r1(void)
+{
+ return &curve_secp256r1;
+}
+
+void vli_mmod_fast_secp256r1(unsigned int *result, unsigned int*product)
+{
+ unsigned int tmp[NUM_ECC_WORDS];
+ int carry;
+
+ /* t */
+ uECC_vli_set(result, product, NUM_ECC_WORDS);
+
+ /* s1 */
+ tmp[0] = tmp[1] = tmp[2] = 0;
+ tmp[3] = product[11];
+ tmp[4] = product[12];
+ tmp[5] = product[13];
+ tmp[6] = product[14];
+ tmp[7] = product[15];
+ carry = uECC_vli_add(tmp, tmp, tmp, NUM_ECC_WORDS);
+ carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
+
+ /* s2 */
+ tmp[3] = product[12];
+ tmp[4] = product[13];
+ tmp[5] = product[14];
+ tmp[6] = product[15];
+ tmp[7] = 0;
+ carry += uECC_vli_add(tmp, tmp, tmp, NUM_ECC_WORDS);
+ carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
+
+ /* s3 */
+ tmp[0] = product[8];
+ tmp[1] = product[9];
+ tmp[2] = product[10];
+ tmp[3] = tmp[4] = tmp[5] = 0;
+ tmp[6] = product[14];
+ tmp[7] = product[15];
+ carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
+
+ /* s4 */
+ tmp[0] = product[9];
+ tmp[1] = product[10];
+ tmp[2] = product[11];
+ tmp[3] = product[13];
+ tmp[4] = product[14];
+ tmp[5] = product[15];
+ tmp[6] = product[13];
+ tmp[7] = product[8];
+ carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
+
+ /* d1 */
+ tmp[0] = product[11];
+ tmp[1] = product[12];
+ tmp[2] = product[13];
+ tmp[3] = tmp[4] = tmp[5] = 0;
+ tmp[6] = product[8];
+ tmp[7] = product[10];
+ carry -= uECC_vli_sub(result, result, tmp, NUM_ECC_WORDS);
+
+ /* d2 */
+ tmp[0] = product[12];
+ tmp[1] = product[13];
+ tmp[2] = product[14];
+ tmp[3] = product[15];
+ tmp[4] = tmp[5] = 0;
+ tmp[6] = product[9];
+ tmp[7] = product[11];
+ carry -= uECC_vli_sub(result, result, tmp, NUM_ECC_WORDS);
+
+ /* d3 */
+ tmp[0] = product[13];
+ tmp[1] = product[14];
+ tmp[2] = product[15];
+ tmp[3] = product[8];
+ tmp[4] = product[9];
+ tmp[5] = product[10];
+ tmp[6] = 0;
+ tmp[7] = product[12];
+ carry -= uECC_vli_sub(result, result, tmp, NUM_ECC_WORDS);
+
+ /* d4 */
+ tmp[0] = product[14];
+ tmp[1] = product[15];
+ tmp[2] = 0;
+ tmp[3] = product[9];
+ tmp[4] = product[10];
+ tmp[5] = product[11];
+ tmp[6] = 0;
+ tmp[7] = product[13];
+ carry -= uECC_vli_sub(result, result, tmp, NUM_ECC_WORDS);
+
+ if (carry < 0) {
+ do {
+ carry += uECC_vli_add(result, result, curve_secp256r1.p, NUM_ECC_WORDS);
+ }
+ while (carry < 0);
+ } else {
+ while (carry ||
+ uECC_vli_cmp_unsafe(curve_secp256r1.p, result, NUM_ECC_WORDS) != 1) {
+ carry -= uECC_vli_sub(result, result, curve_secp256r1.p, NUM_ECC_WORDS);
+ }
+ }
+}
+
+uECC_word_t EccPoint_isZero(const uECC_word_t *point, uECC_Curve curve)
+{
+ return uECC_vli_isZero(point, curve->num_words * 2);
+}
+
+void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z,
+ uECC_Curve curve)
+{
+ uECC_word_t t1[NUM_ECC_WORDS];
+
+ uECC_vli_modSquare_fast(t1, Z, curve); /* z^2 */
+ uECC_vli_modMult_fast(X1, X1, t1, curve); /* x1 * z^2 */
+ uECC_vli_modMult_fast(t1, t1, Z, curve); /* z^3 */
+ uECC_vli_modMult_fast(Y1, Y1, t1, curve); /* y1 * z^3 */
+}
+
+/* P = (x1, y1) => 2P, (x2, y2) => P' */
+static void XYcZ_initial_double(uECC_word_t * X1, uECC_word_t * Y1,
+ uECC_word_t * X2, uECC_word_t * Y2,
+ const uECC_word_t * const initial_Z,
+ uECC_Curve curve)
+{
+ uECC_word_t z[NUM_ECC_WORDS];
+ wordcount_t num_words = curve->num_words;
+ if (initial_Z) {
+ uECC_vli_set(z, initial_Z, num_words);
+ } else {
+ uECC_vli_clear(z, num_words);
+ z[0] = 1;
+ }
+
+ 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);
+ apply_z(X2, Y2, z, curve);
+}
+
+void XYcZ_add(uECC_word_t * X1, uECC_word_t * Y1,
+ uECC_word_t * X2, uECC_word_t * Y2,
+ uECC_Curve curve)
+{
+ /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
+ uECC_word_t t5[NUM_ECC_WORDS];
+ wordcount_t num_words = curve->num_words;
+
+ 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, 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, 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, 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, num_words); /* t4 = y3 */
+
+ uECC_vli_set(X2, t5, num_words);
+}
+
+/* Input P = (x1, y1, Z), Q = (x2, y2, Z)
+ Output P + Q = (x3, y3, Z3), P - Q = (x3', y3', Z3)
+ or P => P - Q, Q => P + Q
+ */
+static void XYcZ_addC(uECC_word_t * X1, uECC_word_t * Y1,
+ uECC_word_t * X2, uECC_word_t * Y2,
+ uECC_Curve curve)
+{
+ /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
+ uECC_word_t t5[NUM_ECC_WORDS];
+ uECC_word_t t6[NUM_ECC_WORDS];
+ uECC_word_t t7[NUM_ECC_WORDS];
+ wordcount_t num_words = curve->num_words;
+
+ 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, 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, 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, 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, num_words); /* t3 = D - (B + C) = 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) */
+ /* t4 = (y2 - y1)*(B - x3) - E = y3: */
+ uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words);
+
+ uECC_vli_modSquare_fast(t7, t5, curve); /* t7 = (y2 + y1)^2 = F */
+ 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) */
+ /* t2 = (y2+y1)*(x3' - B) - E = y3': */
+ uECC_vli_modSub(Y1, t6, Y1, curve->p, num_words);
+
+ uECC_vli_set(X1, t7, num_words);
+}
+
+void EccPoint_mult(uECC_word_t * result, const uECC_word_t * point,
+ const uECC_word_t * scalar,
+ const uECC_word_t * initial_Z,
+ bitcount_t num_bits, uECC_Curve curve)
+{
+ /* R0 and R1 */
+ uECC_word_t Rx[2][NUM_ECC_WORDS];
+ uECC_word_t Ry[2][NUM_ECC_WORDS];
+ uECC_word_t z[NUM_ECC_WORDS];
+ bitcount_t i;
+ uECC_word_t nb;
+ wordcount_t 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);
+
+ for (i = num_bits - 2; i > 0; --i) {
+ nb = !uECC_vli_testBit(scalar, i);
+ XYcZ_addC(Rx[1 - nb], Ry[1 - nb], Rx[nb], Ry[nb], curve);
+ XYcZ_add(Rx[nb], Ry[nb], Rx[1 - nb], Ry[1 - nb], curve);
+ }
+
+ nb = !uECC_vli_testBit(scalar, 0);
+ 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, 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, num_words); /* 1 / (xP * Yb * (X1 - X0))*/
+ /* yP / (xP * Yb * (X1 - X0)) */
+ uECC_vli_modMult_fast(z, z, point + num_words, curve);
+ /* Xb * yP / (xP * Yb * (X1 - X0)) */
+ uECC_vli_modMult_fast(z, z, Rx[1 - nb], curve);
+ /* 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], num_words);
+ uECC_vli_set(result + num_words, Ry[0], num_words);
+}
+
+uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0,
+ uECC_word_t *k1, uECC_Curve curve)
+{
+
+ wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+
+ bitcount_t num_n_bits = curve->num_n_bits;
+
+ uECC_word_t carry = uECC_vli_add(k0, k, curve->n, num_n_words) ||
+ (num_n_bits < ((bitcount_t)num_n_words * uECC_WORD_SIZE * 8) &&
+ uECC_vli_testBit(k0, num_n_bits));
+
+ uECC_vli_add(k1, k0, curve->n, num_n_words);
+
+ return carry;
+}
+
+uECC_word_t EccPoint_compute_public_key(uECC_word_t *result,
+ uECC_word_t *private_key,
+ uECC_Curve curve)
+{
+
+ uECC_word_t tmp1[NUM_ECC_WORDS];
+ uECC_word_t tmp2[NUM_ECC_WORDS];
+ uECC_word_t *p2[2] = {tmp1, tmp2};
+ uECC_word_t carry;
+
+ /* Regularize the bitcount for the private key so that attackers cannot
+ * use a side channel attack to learn the number of leading zeros. */
+ carry = regularize_k(private_key, tmp1, tmp2, curve);
+
+ EccPoint_mult(result, curve->G, p2[!carry], 0, curve->num_n_bits + 1, curve);
+
+ if (EccPoint_isZero(result, curve)) {
+ return 0;
+ }
+ return 1;
+}
+
+/* Converts an integer in uECC native format to big-endian bytes. */
+void uECC_vli_nativeToBytes(uint8_t *bytes, int num_bytes,
+ const unsigned int *native)
+{
+ wordcount_t i;
+ for (i = 0; i < num_bytes; ++i) {
+ unsigned b = num_bytes - 1 - i;
+ bytes[i] = native[b / uECC_WORD_SIZE] >> (8 * (b % uECC_WORD_SIZE));
+ }
+}
+
+/* Converts big-endian bytes to an integer in uECC native format. */
+void uECC_vli_bytesToNative(unsigned int *native, const uint8_t *bytes,
+ int num_bytes)
+{
+ wordcount_t i;
+ uECC_vli_clear(native, (num_bytes + (uECC_WORD_SIZE - 1)) / uECC_WORD_SIZE);
+ for (i = 0; i < num_bytes; ++i) {
+ unsigned b = num_bytes - 1 - i;
+ native[b / uECC_WORD_SIZE] |=
+ (uECC_word_t)bytes[i] << (8 * (b % uECC_WORD_SIZE));
+ }
+}
+
+int uECC_generate_random_int(uECC_word_t *random, const uECC_word_t *top,
+ wordcount_t num_words)
+{
+ uECC_word_t mask = (uECC_word_t)-1;
+ uECC_word_t tries;
+ bitcount_t num_bits = uECC_vli_numBits(top, num_words);
+
+ if (!g_rng_function) {
+ return 0;
+ }
+
+ for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) {
+ if (!g_rng_function((uint8_t *)random, num_words * uECC_WORD_SIZE)) {
+ return 0;
+ }
+ random[num_words - 1] &=
+ mask >> ((bitcount_t)(num_words * uECC_WORD_SIZE * 8 - num_bits));
+ if (!uECC_vli_isZero(random, num_words) &&
+ uECC_vli_cmp(top, random, num_words) == 1) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
+
+int uECC_valid_point(const uECC_word_t *point, uECC_Curve curve)
+{
+ uECC_word_t tmp1[NUM_ECC_WORDS];
+ uECC_word_t tmp2[NUM_ECC_WORDS];
+ wordcount_t num_words = curve->num_words;
+
+ /* The point at infinity is invalid. */
+ if (EccPoint_isZero(point, curve)) {
+ return -1;
+ }
+
+ /* x and y must be smaller than p. */
+ if (uECC_vli_cmp_unsafe(curve->p, point, num_words) != 1 ||
+ uECC_vli_cmp_unsafe(curve->p, point + num_words, num_words) != 1) {
+ return -2;
+ }
+
+ 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 */
+ if (uECC_vli_equal(tmp1, tmp2, num_words) != 0)
+ return -3;
+
+ return 0;
+}
+
+int uECC_valid_public_key(const uint8_t *public_key, uECC_Curve curve)
+{
+
+ uECC_word_t _public[NUM_ECC_WORDS * 2];
+
+ uECC_vli_bytesToNative(_public, public_key, curve->num_bytes);
+ uECC_vli_bytesToNative(
+ _public + curve->num_words,
+ public_key + curve->num_bytes,
+ curve->num_bytes);
+
+ if (uECC_vli_cmp_unsafe(_public, curve->G, NUM_ECC_WORDS * 2) == 0) {
+ return -4;
+ }
+
+ return uECC_valid_point(_public, curve);
+}
+
+int uECC_compute_public_key(const uint8_t *private_key, uint8_t *public_key,
+ uECC_Curve curve)
+{
+
+ uECC_word_t _private[NUM_ECC_WORDS];
+ uECC_word_t _public[NUM_ECC_WORDS * 2];
+
+ uECC_vli_bytesToNative(
+ _private,
+ private_key,
+ BITS_TO_BYTES(curve->num_n_bits));
+
+ /* Make sure the private key is in the range [1, n-1]. */
+ if (uECC_vli_isZero(_private, BITS_TO_WORDS(curve->num_n_bits))) {
+ return 0;
+ }
+
+ if (uECC_vli_cmp(curve->n, _private, BITS_TO_WORDS(curve->num_n_bits)) != 1) {
+ return 0;
+ }
+
+ /* Compute public key. */
+ if (!EccPoint_compute_public_key(_public, _private, curve)) {
+ return 0;
+ }
+
+ uECC_vli_nativeToBytes(public_key, curve->num_bytes, _public);
+ uECC_vli_nativeToBytes(
+ public_key +
+ curve->num_bytes, curve->num_bytes, _public + curve->num_words);
+ return 1;
+}
+
+
+
diff --git a/tinycrypt/ecc_dh.c b/tinycrypt/ecc_dh.c
new file mode 100644
index 0000000..e5257d2
--- /dev/null
+++ b/tinycrypt/ecc_dh.c
@@ -0,0 +1,200 @@
+/* ec_dh.c - TinyCrypt implementation of EC-DH */
+
+/*
+ * Copyright (c) 2014, Kenneth MacKay
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Copyright (C) 2017 by Intel Corporation, All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of Intel Corporation nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <tinycrypt/constants.h>
+#include <tinycrypt/ecc.h>
+#include <tinycrypt/ecc_dh.h>
+#include <string.h>
+
+#if default_RNG_defined
+static uECC_RNG_Function g_rng_function = &default_CSPRNG;
+#else
+static uECC_RNG_Function g_rng_function = 0;
+#endif
+
+int uECC_make_key_with_d(uint8_t *public_key, uint8_t *private_key,
+ unsigned int *d, uECC_Curve curve)
+{
+
+ uECC_word_t _private[NUM_ECC_WORDS];
+ uECC_word_t _public[NUM_ECC_WORDS * 2];
+
+ /* This function is designed for test purposes-only (such as validating NIST
+ * test vectors) as it uses a provided value for d instead of generating
+ * it uniformly at random. */
+ memcpy (_private, d, NUM_ECC_BYTES);
+
+ /* Computing public-key from private: */
+ if (EccPoint_compute_public_key(_public, _private, curve)) {
+
+ /* Converting buffers to correct bit order: */
+ uECC_vli_nativeToBytes(private_key,
+ BITS_TO_BYTES(curve->num_n_bits),
+ _private);
+ uECC_vli_nativeToBytes(public_key,
+ curve->num_bytes,
+ _public);
+ uECC_vli_nativeToBytes(public_key + curve->num_bytes,
+ curve->num_bytes,
+ _public + curve->num_words);
+
+ /* erasing temporary buffer used to store secret: */
+ memset(_private, 0, NUM_ECC_BYTES);
+
+ return 1;
+ }
+ return 0;
+}
+
+int uECC_make_key(uint8_t *public_key, uint8_t *private_key, uECC_Curve curve)
+{
+
+ uECC_word_t _random[NUM_ECC_WORDS * 2];
+ uECC_word_t _private[NUM_ECC_WORDS];
+ uECC_word_t _public[NUM_ECC_WORDS * 2];
+ uECC_word_t tries;
+
+ for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) {
+ /* Generating _private uniformly at random: */
+ uECC_RNG_Function rng_function = uECC_get_rng();
+ if (!rng_function ||
+ !rng_function((uint8_t *)_random, 2 * NUM_ECC_WORDS*uECC_WORD_SIZE)) {
+ return 0;
+ }
+
+ /* computing modular reduction of _random (see FIPS 186.4 B.4.1): */
+ uECC_vli_mmod(_private, _random, curve->n, BITS_TO_WORDS(curve->num_n_bits));
+
+ /* Computing public-key from private: */
+ if (EccPoint_compute_public_key(_public, _private, curve)) {
+
+ /* Converting buffers to correct bit order: */
+ uECC_vli_nativeToBytes(private_key,
+ BITS_TO_BYTES(curve->num_n_bits),
+ _private);
+ uECC_vli_nativeToBytes(public_key,
+ curve->num_bytes,
+ _public);
+ uECC_vli_nativeToBytes(public_key + curve->num_bytes,
+ curve->num_bytes,
+ _public + curve->num_words);
+
+ /* erasing temporary buffer that stored secret: */
+ memset(_private, 0, NUM_ECC_BYTES);
+
+ return 1;
+ }
+ }
+ return 0;
+}
+
+int uECC_shared_secret(const uint8_t *public_key, const uint8_t *private_key,
+ uint8_t *secret, uECC_Curve curve)
+{
+
+ uECC_word_t _public[NUM_ECC_WORDS * 2];
+ uECC_word_t _private[NUM_ECC_WORDS];
+
+ uECC_word_t tmp[NUM_ECC_WORDS];
+ uECC_word_t *p2[2] = {_private, tmp};
+ uECC_word_t *initial_Z = 0;
+ uECC_word_t carry;
+ wordcount_t num_words = curve->num_words;
+ wordcount_t num_bytes = curve->num_bytes;
+ int r;
+
+ /* Converting buffers to correct bit order: */
+ uECC_vli_bytesToNative(_private,
+ private_key,
+ BITS_TO_BYTES(curve->num_n_bits));
+ uECC_vli_bytesToNative(_public,
+ public_key,
+ num_bytes);
+ uECC_vli_bytesToNative(_public + num_words,
+ public_key + num_bytes,
+ num_bytes);
+
+ /* Regularize the bitcount for the private key so that attackers cannot use a
+ * side channel attack to learn the number of leading zeros. */
+ carry = regularize_k(_private, _private, tmp, curve);
+
+ /* If an RNG function was specified, try to get a random initial Z value to
+ * improve protection against side-channel attacks. */
+ if (g_rng_function) {
+ if (!uECC_generate_random_int(p2[carry], curve->p, num_words)) {
+ r = 0;
+ goto clear_and_out;
+ }
+ initial_Z = p2[carry];
+ }
+
+ EccPoint_mult(_public, _public, p2[!carry], initial_Z, curve->num_n_bits + 1,
+ curve);
+
+ uECC_vli_nativeToBytes(secret, num_bytes, _public);
+ r = !EccPoint_isZero(_public, curve);
+
+clear_and_out:
+ /* erasing temporary buffer used to store secret: */
+ memset(p2, 0, sizeof(p2));
+ __asm__ __volatile__("" :: "g"(p2) : "memory");
+ memset(tmp, 0, sizeof(tmp));
+ __asm__ __volatile__("" :: "g"(tmp) : "memory");
+ memset(_private, 0, sizeof(_private));
+ __asm__ __volatile__("" :: "g"(_private) : "memory");
+
+ return r;
+}
diff --git a/tinycrypt/ecc_dsa.c b/tinycrypt/ecc_dsa.c
new file mode 100644
index 0000000..064dfe5
--- /dev/null
+++ b/tinycrypt/ecc_dsa.c
@@ -0,0 +1,295 @@
+/* ec_dsa.c - TinyCrypt implementation of EC-DSA */
+
+/* Copyright (c) 2014, Kenneth MacKay
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.*/
+
+/*
+ * Copyright (C) 2017 by Intel Corporation, All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of Intel Corporation nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <tinycrypt/constants.h>
+#include <tinycrypt/ecc.h>
+#include <tinycrypt/ecc_dsa.h>
+
+#if default_RNG_defined
+static uECC_RNG_Function g_rng_function = &default_CSPRNG;
+#else
+static uECC_RNG_Function g_rng_function = 0;
+#endif
+
+static void bits2int(uECC_word_t *native, const uint8_t *bits,
+ unsigned bits_size, uECC_Curve curve)
+{
+ unsigned num_n_bytes = BITS_TO_BYTES(curve->num_n_bits);
+ unsigned num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+ int shift;
+ uECC_word_t carry;
+ uECC_word_t *ptr;
+
+ if (bits_size > num_n_bytes) {
+ bits_size = num_n_bytes;
+ }
+
+ uECC_vli_clear(native, num_n_words);
+ uECC_vli_bytesToNative(native, bits, bits_size);
+ if (bits_size * 8 <= (unsigned)curve->num_n_bits) {
+ return;
+ }
+ shift = bits_size * 8 - curve->num_n_bits;
+ carry = 0;
+ ptr = native + num_n_words;
+ while (ptr-- > native) {
+ uECC_word_t temp = *ptr;
+ *ptr = (temp >> shift) | carry;
+ carry = temp << (uECC_WORD_BITS - shift);
+ }
+
+ /* Reduce mod curve_n */
+ if (uECC_vli_cmp_unsafe(curve->n, native, num_n_words) != 1) {
+ uECC_vli_sub(native, native, curve->n, num_n_words);
+ }
+}
+
+int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash,
+ unsigned hash_size, uECC_word_t *k, uint8_t *signature,
+ uECC_Curve curve)
+{
+
+ uECC_word_t tmp[NUM_ECC_WORDS];
+ uECC_word_t s[NUM_ECC_WORDS];
+ uECC_word_t *k2[2] = {tmp, s};
+ uECC_word_t p[NUM_ECC_WORDS * 2];
+ uECC_word_t carry;
+ wordcount_t num_words = curve->num_words;
+ wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+ bitcount_t num_n_bits = curve->num_n_bits;
+
+ /* Make sure 0 < k < curve_n */
+ 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, num_words)) {
+ return 0;
+ }
+
+ /* If an RNG function was specified, get a random number
+ to prevent side channel analysis of k. */
+ if (!g_rng_function) {
+ uECC_vli_clear(tmp, num_n_words);
+ tmp[0] = 1;
+ }
+ else if (!uECC_generate_random_int(tmp, curve->n, num_n_words)) {
+ return 0;
+ }
+
+ /* 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, 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, curve->num_bytes, p); /* store r */
+
+ /* tmp = d: */
+ uECC_vli_bytesToNative(tmp, private_key, BITS_TO_BYTES(curve->num_n_bits));
+
+ 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 */
+
+ bits2int(tmp, message_hash, hash_size, curve);
+ 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, curve->num_bytes, s);
+ return 1;
+}
+
+int uECC_sign(const uint8_t *private_key, const uint8_t *message_hash,
+ unsigned hash_size, uint8_t *signature, uECC_Curve curve)
+{
+ uECC_word_t _random[2*NUM_ECC_WORDS];
+ uECC_word_t k[NUM_ECC_WORDS];
+ uECC_word_t tries;
+
+ for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) {
+ /* Generating _random uniformly at random: */
+ uECC_RNG_Function rng_function = uECC_get_rng();
+ if (!rng_function ||
+ !rng_function((uint8_t *)_random, 2*NUM_ECC_WORDS*uECC_WORD_SIZE)) {
+ return 0;
+ }
+
+ // computing k as modular reduction of _random (see FIPS 186.4 B.5.1):
+ uECC_vli_mmod(k, _random, curve->n, BITS_TO_WORDS(curve->num_n_bits));
+
+ if (uECC_sign_with_k(private_key, message_hash, hash_size, k, signature,
+ curve)) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
+static bitcount_t smax(bitcount_t a, bitcount_t b)
+{
+ return (a > b ? a : b);
+}
+
+int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
+ unsigned hash_size, const uint8_t *signature,
+ uECC_Curve curve)
+{
+
+ uECC_word_t u1[NUM_ECC_WORDS], u2[NUM_ECC_WORDS];
+ uECC_word_t z[NUM_ECC_WORDS];
+ uECC_word_t sum[NUM_ECC_WORDS * 2];
+ uECC_word_t rx[NUM_ECC_WORDS];
+ uECC_word_t ry[NUM_ECC_WORDS];
+ uECC_word_t tx[NUM_ECC_WORDS];
+ uECC_word_t ty[NUM_ECC_WORDS];
+ uECC_word_t tz[NUM_ECC_WORDS];
+ const uECC_word_t *points[4];
+ const uECC_word_t *point;
+ bitcount_t num_bits;
+ bitcount_t i;
+
+ uECC_word_t _public[NUM_ECC_WORDS * 2];
+ uECC_word_t r[NUM_ECC_WORDS], s[NUM_ECC_WORDS];
+ wordcount_t num_words = curve->num_words;
+ wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+
+ 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->num_bytes);
+ uECC_vli_bytesToNative(_public + num_words, public_key + curve->num_bytes,
+ curve->num_bytes);
+ uECC_vli_bytesToNative(r, signature, curve->num_bytes);
+ uECC_vli_bytesToNative(s, signature + curve->num_bytes, curve->num_bytes);
+
+ /* r, s must not be 0. */
+ if (uECC_vli_isZero(r, num_words) || uECC_vli_isZero(s, num_words)) {
+ return 0;
+ }
+
+ /* r, s must be < n. */
+ if (uECC_vli_cmp_unsafe(curve->n, r, num_n_words) != 1 ||
+ uECC_vli_cmp_unsafe(curve->n, s, num_n_words) != 1) {
+ return 0;
+ }
+
+ /* Calculate u1 and u2. */
+ uECC_vli_modInv(z, s, curve->n, num_n_words); /* z = 1/s */
+ u1[num_n_words - 1] = 0;
+ bits2int(u1, message_hash, hash_size, curve);
+ 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, 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, 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, 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) {
+ uECC_word_t index;
+ curve->double_jacobian(rx, ry, z, curve);
+
+ index = (!!uECC_vli_testBit(u1, i)) | ((!!uECC_vli_testBit(u2, i)) << 1);
+ point = points[index];
+ if (point) {
+ 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, 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, num_words); /* Z = 1/Z */
+ apply_z(rx, ry, z, curve);
+
+ /* v = x1 (mod n) */
+ if (uECC_vli_cmp_unsafe(curve->n, rx, num_n_words) != 1) {
+ uECC_vli_sub(rx, rx, curve->n, num_n_words);
+ }
+
+ /* Accept only if v == r. */
+ return (int)(uECC_vli_equal(rx, r, num_words) == 0);
+}
+