diff --git a/include/tinycrypt/ecc.h b/include/tinycrypt/ecc.h index 75e6e9213..dccfdf423 100644 --- a/include/tinycrypt/ecc.h +++ b/include/tinycrypt/ecc.h @@ -124,7 +124,6 @@ typedef uint64_t uECC_dword_t; struct uECC_Curve_t; typedef const struct uECC_Curve_t * uECC_Curve; struct uECC_Curve_t { - uECC_word_t n[NUM_ECC_WORDS]; uECC_word_t G[NUM_ECC_WORDS * 2]; uECC_word_t b[NUM_ECC_WORDS]; }; @@ -155,15 +154,11 @@ void vli_mmod_fast_secp256r1(unsigned int *result, unsigned int *product); #define BITS_TO_BYTES(num_bits) ((num_bits + 7) / 8) extern const uECC_word_t curve_p[NUM_ECC_WORDS]; +extern const uECC_word_t curve_n[NUM_ECC_WORDS]; /* definition of curve NIST p-256: */ static const struct uECC_Curve_t curve_secp256r1 = { { - BYTES_TO_WORDS_8(51, 25, 63, FC, C2, CA, B9, F3), - BYTES_TO_WORDS_8(84, 9E, 17, A7, AD, FA, E6, BC), - BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF), - BYTES_TO_WORDS_8(00, 00, 00, 00, FF, FF, FF, FF) - }, { BYTES_TO_WORDS_8(96, C2, 98, D8, 45, 39, A1, F4), BYTES_TO_WORDS_8(A0, 33, EB, 2D, 81, 7D, 03, 77), BYTES_TO_WORDS_8(F2, 40, A4, 63, E5, E6, BC, F8), diff --git a/tinycrypt/ecc.c b/tinycrypt/ecc.c index 6f96bd939..daa9698a3 100644 --- a/tinycrypt/ecc.c +++ b/tinycrypt/ecc.c @@ -75,6 +75,12 @@ const uECC_word_t curve_p[NUM_ECC_WORDS] = { BYTES_TO_WORDS_8(00, 00, 00, 00, 00, 00, 00, 00), BYTES_TO_WORDS_8(01, 00, 00, 00, FF, FF, FF, FF) }; +const uECC_word_t curve_n[NUM_ECC_WORDS] = { + BYTES_TO_WORDS_8(51, 25, 63, FC, C2, CA, B9, F3), + BYTES_TO_WORDS_8(84, 9E, 17, A7, AD, FA, E6, BC), + BYTES_TO_WORDS_8(FF, FF, FF, FF, FF, FF, FF, FF), + BYTES_TO_WORDS_8(00, 00, 00, 00, FF, FF, FF, FF) +}; /* IMPORTANT: Make sure a cryptographically-secure PRNG is set and the platform * has access to enough entropy in order to feed the PRNG regularly. */ @@ -933,13 +939,12 @@ static uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0, wordcount_t num_n_words = NUM_ECC_WORDS; bitcount_t num_n_bits = NUM_ECC_BITS; - const uECC_Curve curve = uECC_secp256r1(); - uECC_word_t carry = uECC_vli_add(k0, k, curve->n) || + uECC_word_t carry = uECC_vli_add(k0, k, curve_n) || (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); + uECC_vli_add(k1, k0, curve_n); return carry; } @@ -1116,7 +1121,7 @@ int uECC_compute_public_key(const uint8_t *private_key, uint8_t *public_key, return 0; } - if (uECC_vli_cmp(curve->n, _private) != 1) { + if (uECC_vli_cmp(curve_n, _private) != 1) { return 0; } diff --git a/tinycrypt/ecc_dh.c b/tinycrypt/ecc_dh.c index 5c5bc1343..fc429fe47 100644 --- a/tinycrypt/ecc_dh.c +++ b/tinycrypt/ecc_dh.c @@ -123,7 +123,7 @@ int uECC_make_key(uint8_t *public_key, uint8_t *private_key, uECC_Curve curve) } /* computing modular reduction of _random (see FIPS 186.4 B.4.1): */ - uECC_vli_mmod(_private, _random, curve->n); + uECC_vli_mmod(_private, _random, curve_n); /* Computing public-key from private: */ if (EccPoint_compute_public_key(_public, _private, curve)) { diff --git a/tinycrypt/ecc_dsa.c b/tinycrypt/ecc_dsa.c index fc2a3fe3e..c22ebd032 100644 --- a/tinycrypt/ecc_dsa.c +++ b/tinycrypt/ecc_dsa.c @@ -84,6 +84,8 @@ static void bits2int(uECC_word_t *native, const uint8_t *bits, uECC_word_t carry; uECC_word_t *ptr; + (void) curve; + if (bits_size > num_n_bytes) { bits_size = num_n_bytes; } @@ -103,8 +105,8 @@ static void bits2int(uECC_word_t *native, const uint8_t *bits, } /* Reduce mod curve_n */ - if (uECC_vli_cmp_unsafe(curve->n, native) != 1) { - uECC_vli_sub(native, native, curve->n); + if (uECC_vli_cmp_unsafe(curve_n, native) != 1) { + uECC_vli_sub(native, native, curve_n); } } @@ -122,7 +124,7 @@ int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash, /* Make sure 0 < k < curve_n */ if (uECC_vli_isZero(k) || - uECC_vli_cmp(curve->n, k) != 1) { + uECC_vli_cmp(curve_n, k) != 1) { return 0; } @@ -137,15 +139,15 @@ int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash, uECC_vli_clear(tmp); tmp[0] = 1; } - else if (!uECC_generate_random_int(tmp, curve->n, num_n_words)) { + 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); /* k' = rand * k */ - uECC_vli_modInv(k, k, curve->n); /* k = 1 / k' */ - uECC_vli_modMult(k, k, tmp, curve->n); /* k = 1 / k */ + uECC_vli_modMult(k, k, tmp, curve_n); /* k' = rand * k */ + uECC_vli_modInv(k, k, curve_n); /* k = 1 / k' */ + uECC_vli_modMult(k, k, tmp, curve_n); /* k = 1 / k */ uECC_vli_nativeToBytes(signature, NUM_ECC_BYTES, p); /* store r */ @@ -154,11 +156,11 @@ int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash, s[num_n_words - 1] = 0; uECC_vli_set(s, p); - uECC_vli_modMult(s, tmp, s, curve->n); /* s = r*d */ + uECC_vli_modMult(s, tmp, s, curve_n); /* s = r*d */ bits2int(tmp, message_hash, hash_size, curve); - uECC_vli_modAdd(s, tmp, s, curve->n); /* s = e + r*d */ - uECC_vli_modMult(s, s, k, curve->n); /* s = (e + r*d) / k */ + uECC_vli_modAdd(s, tmp, s, curve_n); /* s = e + r*d */ + uECC_vli_modMult(s, s, k, curve_n); /* s = (e + r*d) / k */ if (uECC_vli_numBits(s) > (bitcount_t)NUM_ECC_BYTES * 8) { return 0; } @@ -183,7 +185,7 @@ int uECC_sign(const uint8_t *private_key, const uint8_t *message_hash, } // computing k as modular reduction of _random (see FIPS 186.4 B.5.1): - uECC_vli_mmod(k, _random, curve->n); + uECC_vli_mmod(k, _random, curve_n); if (uECC_sign_with_k(private_key, message_hash, hash_size, k, signature, curve)) { @@ -241,17 +243,17 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash, } /* r, s must be < n. */ - if (uECC_vli_cmp_unsafe(curve->n, r) != 1 || - uECC_vli_cmp_unsafe(curve->n, s) != 1) { + if (uECC_vli_cmp_unsafe(curve_n, r) != 1 || + uECC_vli_cmp_unsafe(curve_n, s) != 1) { return UECC_FAILURE; } /* Calculate u1 and u2. */ - uECC_vli_modInv(z, s, curve->n); /* z = 1/s */ + uECC_vli_modInv(z, s, curve_n); /* z = 1/s */ u1[num_n_words - 1] = 0; bits2int(u1, message_hash, hash_size, curve); - uECC_vli_modMult(u1, u1, z, curve->n); /* u1 = e/s */ - uECC_vli_modMult(u2, r, z, curve->n); /* u2 = r/s */ + uECC_vli_modMult(u1, u1, z, curve_n); /* u1 = e/s */ + uECC_vli_modMult(u2, r, z, curve_n); /* u2 = r/s */ /* Calculate sum = G + Q. */ uECC_vli_set(sum, _public); @@ -298,8 +300,8 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash, apply_z(rx, ry, z); /* v = x1 (mod n) */ - if (uECC_vli_cmp_unsafe(curve->n, rx) != 1) { - uECC_vli_sub(rx, rx, curve->n); + if (uECC_vli_cmp_unsafe(curve_n, rx) != 1) { + uECC_vli_sub(rx, rx, curve_n); } /* Accept only if v == r. */