Merge remote-tracking branch 'public/pr/2876' into baremetal
diff --git a/configs/baremetal_test.h b/configs/baremetal_test.h
index 33b5167..7a03777 100644
--- a/configs/baremetal_test.h
+++ b/configs/baremetal_test.h
@@ -43,6 +43,9 @@
/* Use Mbed TLS' timer implementation for Linux. */
#define MBEDTLS_TIMING_C
+/* Needed for certificates in ssl_opt.sh */
+#define MBEDTLS_FS_IO
+
#undef MBEDTLS_NO_PLATFORM_ENTROPY
#undef MBEDTLS_ENTROPY_MAX_SOURCES
diff --git a/include/tinycrypt/ecc.h b/include/tinycrypt/ecc.h
index 9c53f3e..2da74b3 100644
--- a/include/tinycrypt/ecc.h
+++ b/include/tinycrypt/ecc.h
@@ -111,6 +111,7 @@
#define NUM_ECC_WORDS 8
/* Number of bytes to represent an element of the the curve p-256: */
#define NUM_ECC_BYTES (uECC_WORD_SIZE*NUM_ECC_WORDS)
+#define NUM_ECC_BITS 256
/* structure that represents an elliptic curve (e.g. p256):*/
struct uECC_Curve_t;
@@ -283,31 +284,18 @@
uECC_word_t *private_key, uECC_Curve curve);
/*
- * @brief Regularize the bitcount for the private key so that attackers cannot
- * use a side channel attack to learn the number of leading zeros.
- * @return Regularized k
- * @param k IN -- private-key
- * @param k0 IN/OUT -- regularized k
- * @param k1 IN/OUT -- regularized k
- * @param curve IN -- elliptic curve
- */
-uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0,
- uECC_word_t *k1, uECC_Curve curve);
-
-/*
* @brief Point multiplication algorithm using Montgomery's ladder with co-Z
* coordinates. See http://eprint.iacr.org/2011/338.pdf.
+ * Uses scalar regularization and coordinate randomization (if a global RNG
+ * function is set) in order to protect against some side channel attacks.
* @note Result may overlap point.
* @param result OUT -- returns scalar*point
* @param point IN -- elliptic curve point
* @param scalar IN -- scalar
- * @param initial_Z IN -- initial value for z
- * @param num_bits IN -- number of bits in scalar
* @param curve IN -- elliptic curve
*/
-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);
+int EccPoint_mult_safer(uECC_word_t * result, const uECC_word_t * point,
+ const uECC_word_t * scalar, uECC_Curve curve);
/*
* @brief Constant-time comparison to zero - secure way to compare long integers
@@ -315,7 +303,7 @@
* @param num_words IN -- number of words in the vli
* @return 1 if vli == 0, 0 otherwise.
*/
-uECC_word_t uECC_vli_isZero(const uECC_word_t *vli, wordcount_t num_words);
+uECC_word_t uECC_vli_isZero(const uECC_word_t *vli);
/*
* @brief Check if 'point' is the point at infinity
@@ -332,8 +320,7 @@
* @param num_words IN -- number of words
* @return the sign of left - right
*/
-cmpresult_t uECC_vli_cmp(const uECC_word_t *left, const uECC_word_t *right,
- wordcount_t num_words);
+cmpresult_t uECC_vli_cmp(const uECC_word_t *left, const uECC_word_t *right);
/*
* @brief computes sign of left - right, not in constant time.
@@ -343,8 +330,7 @@
* @param num_words IN -- number of words
* @return the sign of left - right
*/
-cmpresult_t uECC_vli_cmp_unsafe(const uECC_word_t *left, const uECC_word_t *right,
- wordcount_t num_words);
+cmpresult_t uECC_vli_cmp_unsafe(const uECC_word_t *left, const uECC_word_t *right);
/*
* @brief Computes result = (left - right) % mod.
@@ -357,8 +343,7 @@
* @param num_words IN -- number of 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);
+ const uECC_word_t *right, const uECC_word_t *mod);
/*
* @brief Computes P' = (x1', y1', Z3), P + Q = (x3, y3, Z3) or
@@ -380,8 +365,7 @@
* @param Z IN -- z value
* @param curve IN -- elliptic curve
*/
-void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z,
- uECC_Curve curve);
+void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z);
/*
* @brief Check if bit is set.
@@ -402,7 +386,7 @@
* @warning 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);
+ const uECC_word_t *mod);
/*
* @brief Computes modular product (using curve->mmod_fast)
@@ -412,7 +396,7 @@
* @param curve IN -- elliptic curve
*/
void uECC_vli_modMult_fast(uECC_word_t *result, const uECC_word_t *left,
- const uECC_word_t *right, uECC_Curve curve);
+ const uECC_word_t *right);
/*
* @brief Computes result = left - right.
@@ -424,7 +408,7 @@
* @return borrow
*/
uECC_word_t uECC_vli_sub(uECC_word_t *result, const uECC_word_t *left,
- const uECC_word_t *right, wordcount_t num_words);
+ const uECC_word_t *right);
/*
* @brief Constant-time comparison function(secure way to compare long ints)
@@ -433,8 +417,7 @@
* @param num_words IN -- number of words
* @return Returns 0 if left == right, 1 otherwise.
*/
-uECC_word_t uECC_vli_equal(const uECC_word_t *left, const uECC_word_t *right,
- wordcount_t num_words);
+uECC_word_t uECC_vli_equal(const uECC_word_t *left, const uECC_word_t *right);
/*
* @brief Computes (left * right) % mod
@@ -445,8 +428,7 @@
* @param num_words IN -- number of 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);
+ const uECC_word_t *right, const uECC_word_t *mod);
/*
* @brief Computes (1 / input) % mod
@@ -458,7 +440,7 @@
* @param num_words -- number of words
*/
void uECC_vli_modInv(uECC_word_t *result, const uECC_word_t *input,
- const uECC_word_t *mod, wordcount_t num_words);
+ const uECC_word_t *mod);
/*
* @brief Sets dest = src.
@@ -466,8 +448,7 @@
* @param src IN -- origin buffer
* @param num_words IN -- number of words
*/
-void uECC_vli_set(uECC_word_t *dest, const uECC_word_t *src,
- wordcount_t num_words);
+void uECC_vli_set(uECC_word_t *dest, const uECC_word_t *src);
/*
* @brief Computes (left + right) % mod.
@@ -480,8 +461,7 @@
* @param num_words IN -- number of words
*/
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);
+ const uECC_word_t *right, const uECC_word_t *mod);
/*
* @brief Counts the number of bits required to represent vli.
@@ -489,15 +469,14 @@
* @param max_words IN -- number of words
* @return number of bits in given vli
*/
-bitcount_t uECC_vli_numBits(const uECC_word_t *vli,
- const wordcount_t max_words);
+bitcount_t uECC_vli_numBits(const uECC_word_t *vli);
/*
* @brief Erases (set to 0) vli
* @param vli IN -- very long integer
* @param num_words IN -- number of words
*/
-void uECC_vli_clear(uECC_word_t *vli, wordcount_t num_words);
+void uECC_vli_clear(uECC_word_t *vli);
/*
* @brief check if it is a valid point in the curve
diff --git a/library/platform_util.c b/library/platform_util.c
index db46fe9..1a0fefa 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -142,7 +142,10 @@
uint32_t mbedtls_platform_random_in_range( size_t num )
{
-#if !defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
+ /* Temporary force the dummy version - drawing directly from the HRNG
+ * seems to be causing issues, avoid doing that until we understood the
+ * issue, and perhaps we'll need to draw from a DRBG instead. */
+#if 1 || !defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
(void) num;
return 0;
#else
diff --git a/tests/data_files/Readme-x509.txt b/tests/data_files/Readme-x509.txt
index 388865b..850237a 100644
--- a/tests/data_files/Readme-x509.txt
+++ b/tests/data_files/Readme-x509.txt
@@ -107,6 +107,7 @@
_int3_int-ca2_ca.crt: S10 + I3 + I2 + 1
_int3_spurious_int-ca2.crt: S10 + I3 + I1(spurious) + I2
- server11.crt: 3 E, secp256r1 curve
+ -bad.crt.der: S11 with corrupted public key and signature
Certificate revocation lists
----------------------------
diff --git a/tests/data_files/ec_256_pub.der b/tests/data_files/ec_256_pub.der
new file mode 100644
index 0000000..2ba2595
--- /dev/null
+++ b/tests/data_files/ec_256_pub.der
Binary files differ
diff --git a/tests/data_files/server11-bad.crt.der b/tests/data_files/server11-bad.crt.der
new file mode 100644
index 0000000..0a782a7
--- /dev/null
+++ b/tests/data_files/server11-bad.crt.der
Binary files differ
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index a6ad765..cd0b031 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -656,7 +656,6 @@
SKIP_NEXT="YES"
elif ( [ "$__ARG" = "tls1_2" ] || [ "$__ARG" = "dtls1_2" ] ) && \
( [ "$__VAL_MIN" != "3" ] || [ "$__VAL_MAX" != "3" ] ); then
- echo "FORCE SKIP"
SKIP_NEXT="YES"
fi
@@ -2376,6 +2375,17 @@
-C "session hash for extended master secret" \
-S "session hash for extended master secret"
+run_test "Extended Master Secret: both enabled, both enforcing, DTLS" \
+ "$P_SRV dtls=1 debug_level=3 extended_ms=1 enforce_extended_master_secret=1" \
+ "$P_CLI dtls=1 debug_level=3 extended_ms=1 enforce_extended_master_secret=1" \
+ 0 \
+ -c "client hello, adding extended_master_secret extension" \
+ -s "found extended master secret extension" \
+ -s "server hello, adding extended master secret extension" \
+ -c "found extended_master_secret extension" \
+ -c "session hash for extended master secret" \
+ -s "session hash for extended master secret"
+
# Tests for FALLBACK_SCSV
run_test "Fallback SCSV: default" \
@@ -3777,6 +3787,25 @@
-c "! Certificate verification flags"\
-c "bad server certificate (ECDH curve)" # Expect failure only at ECDH params check
+requires_config_enabled MBEDTLS_USE_TINYCRYPT
+run_test "Authentication: DTLS server ECDH p256, client required, server goodcert" \
+ "$P_SRV dtls=1 debug_level=1 key_file=data_files/server11.key.der \
+ crt_file=data_files/server11.crt.der" \
+ "$P_CLI dtls=1 debug_level=3 auth_mode=required" \
+ 0 \
+ -C "bad certificate (EC key curve)"\
+ -C "! Certificate verification flags"\
+ -C "! mbedtls_ssl_handshake returned"
+
+requires_config_enabled MBEDTLS_USE_TINYCRYPT
+run_test "Authentication: DTLS server ECDH p256, client required, server badcert" \
+ "$P_SRV dtls=1 debug_level=1 key_file=data_files/server11.key.der \
+ crt_file=data_files/server11-bad.crt.der" \
+ "$P_CLI dtls=1 debug_level=3 auth_mode=required" \
+ 1 \
+ -c "! Certificate verification flags"\
+ -c "! mbedtls_ssl_handshake returned"
+
run_test "Authentication: server badcert, client none" \
"$P_SRV crt_file=data_files/server5-badsign.crt \
key_file=data_files/server5.key" \
@@ -4825,6 +4854,12 @@
0 \
-c "Ciphersuite is TLS-ECDHE-ECDSA-WITH-"
+run_test "keyUsage srv: ECDSA, digitalSignature -> ECDHE-ECDSA p256" \
+ "$P_SRV dtls=1 key_file=data_files/server11.key.der \
+ crt_file=data_files/server11.crt.der" \
+ "$P_CLI dtls=1 ca_file=data_files/test-ca3.crt.der" \
+ 0 \
+ -c "Ciphersuite is TLS-ECDHE-ECDSA-WITH-"
run_test "keyUsage srv: ECDSA, keyAgreement -> ECDH-" \
"$P_SRV key_file=data_files/server5.key \
@@ -5641,6 +5676,13 @@
0 \
-s "Read from client: 1 bytes read"
+run_test "Small client packet DTLS, ECDHE-ECDSA" \
+ "$P_SRV dtls=1" \
+ "$P_CLI dtls=1 request_size=1 \
+ force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \
+ 0 \
+ -s "Read from client: 1 bytes read"
+
# Tests for small server packets
requires_config_enabled MBEDTLS_SSL_PROTO_SSL3
@@ -5922,6 +5964,13 @@
0 \
-c "Read from server: 1 bytes read"
+run_test "Small server packet DTLS, ECDHE-ECDSA" \
+ "$P_SRV dtls=1 response_size=1" \
+ "$P_CLI dtls=1 \
+ force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \
+ 0 \
+ -c "Read from server: 1 bytes read"
+
# A test for extensions in SSLv3
requires_config_enabled MBEDTLS_SSL_PROTO_SSL3
@@ -6957,6 +7006,24 @@
-c "found supported_point_formats extension" \
-s "server hello, supported_point_formats extension"
+requires_ciphersuite_enabled TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8
+run_test "Force an ECC ciphersuite with CCM in the client side" \
+ "$P_SRV dtls=1 debug_level=3" \
+ "$P_CLI dtls=1 debug_level=3 force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \
+ 0 \
+ -c "client hello, adding supported_elliptic_curves extension" \
+ -c "client hello, adding supported_point_formats extension" \
+ -s "found supported elliptic curves extension" \
+ -s "found supported point formats extension"
+
+requires_ciphersuite_enabled TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8
+run_test "Force an ECC ciphersuite with CCM in the server side" \
+ "$P_SRV dtls=1 debug_level=3 force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM-8" \
+ "$P_CLI dtls=1 debug_level=3" \
+ 0 \
+ -c "found supported_point_formats extension" \
+ -s "server hello, supported_point_formats extension"
+
# Tests for DTLS HelloVerifyRequest
run_test "DTLS cookie: enabled" \
@@ -6981,7 +7048,6 @@
-S "hello verification requested" \
-S "SSL - The requested feature is not available"
-requires_config_enabled MBEDTLS_ERROR_C
run_test "DTLS cookie: default (failing)" \
"$P_SRV dtls=1 debug_level=2 cookies=-1" \
"$P_CLI dtls=1 debug_level=2 hs_timeout=100-400" \
@@ -6990,8 +7056,7 @@
-S "cookie verification passed" \
-S "cookie verification skipped" \
-C "received hello verify request" \
- -S "hello verification requested" \
- -s "SSL - The requested feature is not available"
+ -S "hello verification requested"
requires_ipv6
run_test "DTLS cookie: enabled, IPv6" \
diff --git a/tests/suites/test_suite_pk.data b/tests/suites/test_suite_pk.data
index 5bdbea0..c8f4d70 100644
--- a/tests/suites/test_suite_pk.data
+++ b/tests/suites/test_suite_pk.data
@@ -154,7 +154,7 @@
Check pair #2 (EC, bad, TinyCrypt)
depends_on:MBEDTLS_USE_TINYCRYPT
-mbedtls_pk_check_pair:"data_files/ec_256_pub.pem":"data_files/server5.key":MBEDTLS_ERR_PK_BAD_INPUT_DATA
+mbedtls_pk_check_pair:"data_files/ec_256_pub.der":"data_files/server5.key.der":MBEDTLS_ERR_PK_BAD_INPUT_DATA
Check pair #3 (RSA, OK)
depends_on:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15
diff --git a/tinycrypt/ecc.c b/tinycrypt/ecc.c
index cef1469..d01c676 100644
--- a/tinycrypt/ecc.c
+++ b/tinycrypt/ecc.c
@@ -65,6 +65,7 @@
#if defined(MBEDTLS_USE_TINYCRYPT)
#include <tinycrypt/ecc.h>
+#include "mbedtls/platform_util.h"
#include <string.h>
/* IMPORTANT: Make sure a cryptographically-secure PRNG is set and the platform
@@ -95,19 +96,19 @@
return 2 * curve->num_bytes;
}
-void uECC_vli_clear(uECC_word_t *vli, wordcount_t num_words)
+void uECC_vli_clear(uECC_word_t *vli)
{
wordcount_t i;
- for (i = 0; i < num_words; ++i) {
+ for (i = 0; i < NUM_ECC_WORDS; ++i) {
vli[i] = 0;
}
}
-uECC_word_t uECC_vli_isZero(const uECC_word_t *vli, wordcount_t num_words)
+uECC_word_t uECC_vli_isZero(const uECC_word_t *vli)
{
uECC_word_t bits = 0;
wordcount_t i;
- for (i = 0; i < num_words; ++i) {
+ for (i = 0; i < NUM_ECC_WORDS; ++i) {
bits |= vli[i];
}
return (bits == 0);
@@ -120,27 +121,25 @@
}
/* Counts the number of words in vli. */
-static wordcount_t vli_numDigits(const uECC_word_t *vli,
- const wordcount_t max_words)
+static wordcount_t vli_numDigits(const uECC_word_t *vli)
{
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) {
+ for (i = NUM_ECC_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)
+bitcount_t uECC_vli_numBits(const uECC_word_t *vli)
{
uECC_word_t i;
uECC_word_t digit;
- wordcount_t num_digits = vli_numDigits(vli, max_words);
+ wordcount_t num_digits = vli_numDigits(vli);
if (num_digits == 0) {
return 0;
}
@@ -153,23 +152,21 @@
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)
+void uECC_vli_set(uECC_word_t *dest, const uECC_word_t *src)
{
wordcount_t i;
- for (i = 0; i < num_words; ++i) {
+ for (i = 0; i < NUM_ECC_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)
+ const uECC_word_t *right)
{
wordcount_t i;
- for (i = num_words - 1; i >= 0; --i) {
+ for (i = NUM_ECC_WORDS - 1; i >= 0; --i) {
if (left[i] > right[i]) {
return 1;
} else if (left[i] < right[i]) {
@@ -179,14 +176,13 @@
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 uECC_vli_equal(const uECC_word_t *left, const uECC_word_t *right)
{
uECC_word_t diff = 0;
wordcount_t i;
- for (i = num_words - 1; i >= 0; --i) {
+ for (i = NUM_ECC_WORDS - 1; i >= 0; --i) {
diff |= (left[i] ^ right[i]);
}
return !(diff == 0);
@@ -200,11 +196,11 @@
/* 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)
+ const uECC_word_t *right)
{
uECC_word_t borrow = 0;
wordcount_t i;
- for (i = 0; i < num_words; ++i) {
+ for (i = 0; i < NUM_ECC_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]));
@@ -217,11 +213,11 @@
/* 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)
+ const uECC_word_t *right)
{
uECC_word_t carry = 0;
wordcount_t i;
- for (i = 0; i < num_words; ++i) {
+ for (i = 0; i < NUM_ECC_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]));
@@ -230,22 +226,21 @@
return carry;
}
-cmpresult_t uECC_vli_cmp(const uECC_word_t *left, const uECC_word_t *right,
- wordcount_t num_words)
+cmpresult_t uECC_vli_cmp(const uECC_word_t *left, const uECC_word_t *right)
{
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);
+ uECC_word_t neg = !!uECC_vli_sub(tmp, left, right);
+ uECC_word_t equal = uECC_vli_isZero(tmp);
return (!equal - 2 * neg);
}
/* Computes vli = vli >> 1. */
-static void uECC_vli_rshift1(uECC_word_t *vli, wordcount_t num_words)
+static void uECC_vli_rshift1(uECC_word_t *vli)
{
uECC_word_t *end = vli;
uECC_word_t carry = 0;
- vli += num_words;
+ vli += NUM_ECC_WORDS;
while (vli-- > end) {
uECC_word_t temp = *vli;
*vli = (temp >> 1) | carry;
@@ -253,6 +248,16 @@
}
}
+/* Compute a * b + r, where r is a double-word with high-order word r1 and
+ * low-order word r0, and store the result in the same double-word (r1, r0),
+ * with the carry bit stored in r2.
+ *
+ * (r2, r1, r0) = a * b + (r1, r0):
+ * [in] a, b: operands to be multiplied
+ * [in] r0, r1: low and high-order words of operand to add
+ * [out] r0, r1: low and high-order words of the result
+ * [out] r2: carry
+ */
static void muladd(uECC_word_t a, uECC_word_t b, uECC_word_t *r0,
uECC_word_t *r1, uECC_word_t *r2)
{
@@ -266,15 +271,84 @@
}
-/* 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)
+/* State for implementing random delays in uECC_vli_mult_rnd().
+ *
+ * The state is initialized by randomizing delays and setting i = 0.
+ * Each call to uECC_vli_mult_rnd() uses one byte of delays and increments i.
+ *
+ * Randomized vli multiplication is used only for point operations
+ * (XYcZ_add_rnd() * and XYcZ_addC_rnd()) in scalar multiplication
+ * (ECCPoint_mult()). Those go in pair, and each pair does 14 calls to
+ * uECC_vli_mult_rnd() (6 in XYcZ_add_rnd() and 8 in XYcZ_addC_rnd(),
+ * indirectly through uECC_vli_modMult_rnd().
+ *
+ * Considering this, in order to minimize the number of calls to the RNG
+ * (which impact performance) while keeping the size of the structure low,
+ * make room for 14 randomized vli mults, which corresponds to one step in the
+ * scalar multiplication routine.
+ */
+typedef struct {
+ uint8_t i;
+ uint8_t delays[14];
+} ecc_wait_state_t;
+
+/*
+ * Reset wait_state so that it's ready to be used.
+ */
+void ecc_wait_state_reset(ecc_wait_state_t *ws)
+{
+ if (ws == NULL)
+ return;
+
+ ws->i = 0;
+ g_rng_function(ws->delays, sizeof(ws->delays));
+}
+
+/* Computes result = left * right. Result must be 2 * num_words long.
+ *
+ * As a counter-measure against horizontal attacks, add noise by performing
+ * a random number of extra computations performing random additional accesses
+ * to limbs of the input.
+ *
+ * Each of the two actual computation loops is surrounded by two
+ * similar-looking waiting loops, to make the beginning and end of the actual
+ * computation harder to spot.
+ *
+ * We add 4 waiting loops of between 0 and 3 calls to muladd() each. That
+ * makes an average of 6 extra calls. Compared to the main computation which
+ * makes 64 such calls, this represents an average performance degradation of
+ * less than 10%.
+ *
+ * Compared to the original uECC_vli_mult(), loose the num_words argument as we
+ * know it's always 8. This saves a bit of code size and execution speed.
+ */
+static void uECC_vli_mult_rnd(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, ecc_wait_state_t *s)
{
uECC_word_t r0 = 0;
uECC_word_t r1 = 0;
uECC_word_t r2 = 0;
wordcount_t i, k;
+ const uint8_t num_words = NUM_ECC_WORDS;
+
+ /* Fetch 8 bit worth of delay from the state; 0 if we have no state */
+ uint8_t delays = s ? s->delays[s->i++] : 0;
+ uECC_word_t rr0 = 0, rr1 = 0;
+ volatile uECC_word_t r;
+
+ /* Mimic start of next loop: k in [0, 3] */
+ k = 0 + (delays & 0x03);
+ delays >>= 2;
+ /* k = 0 -> i in [1, 0] -> 0 extra muladd;
+ * k = 3 -> i in [1, 3] -> 3 extra muladd */
+ for (i = 1; i <= k; ++i) {
+ muladd(left[i], right[k - i], &rr0, &rr1, &r2);
+ }
+ r = rr0;
+ rr0 = rr1;
+ rr1 = r2;
+ r2 = 0;
/* Compute each digit of result in sequence, maintaining the carries. */
for (k = 0; k < num_words; ++k) {
@@ -289,6 +363,32 @@
r2 = 0;
}
+ /* Mimic end of previous loop: k in [4, 7] */
+ k = 4 + (delays & 0x03);
+ delays >>= 2;
+ /* k = 4 -> i in [5, 4] -> 0 extra muladd;
+ * k = 7 -> i in [5, 7] -> 3 extra muladd */
+ for (i = 5; i <= k; ++i) {
+ muladd(left[i], right[k - i], &rr0, &rr1, &r2);
+ }
+ r = rr0;
+ rr0 = rr1;
+ rr1 = r2;
+ r2 = 0;
+
+ /* Mimic start of next loop: k in [8, 11] */
+ k = 11 - (delays & 0x03);
+ delays >>= 2;
+ /* k = 8 -> i in [5, 7] -> 3 extra muladd;
+ * k = 11 -> i in [8, 7] -> 0 extra muladd */
+ for (i = (k + 5) - num_words; i < num_words; ++i) {
+ muladd(left[i], right[k - i], &rr0, &rr1, &r2);
+ }
+ r = rr0;
+ rr0 = rr1;
+ rr1 = r2;
+ r2 = 0;
+
for (k = num_words; k < num_words * 2 - 1; ++k) {
for (i = (k + 1) - num_words; i < num_words; ++i) {
@@ -299,57 +399,73 @@
r1 = r2;
r2 = 0;
}
+
result[num_words * 2 - 1] = r0;
+
+ /* Mimic end of previous loop: k in [12, 15] */
+ k = 15 - (delays & 0x03);
+ delays >>= 2;
+ /* k = 12 -> i in [5, 7] -> 3 extra muladd;
+ * k = 15 -> i in [8, 7] -> 0 extra muladd */
+ for (i = (k + 1) - num_words; i < num_words; ++i) {
+ muladd(left[i], right[k - i], &rr0, &rr1, &r2);
+ }
+ r = rr0;
+ rr0 = rr1;
+ rr1 = r2;
+ r2 = 0;
+
+ /* avoid warning that r is set but not used */
+ (void) r;
}
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)
+ const uECC_word_t *right, const uECC_word_t *mod)
{
- uECC_word_t carry = uECC_vli_add(result, left, right, num_words);
- if (carry || uECC_vli_cmp_unsafe(mod, result, num_words) != 1) {
+ uECC_word_t carry = uECC_vli_add(result, left, right);
+ if (carry || uECC_vli_cmp_unsafe(mod, result) != 1) {
/* result > mod (result = mod + remainder), so subtract mod to get
* remainder. */
- uECC_vli_sub(result, result, mod, num_words);
+ uECC_vli_sub(result, result, mod);
}
}
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)
+ const uECC_word_t *right, const uECC_word_t *mod)
{
- uECC_word_t l_borrow = uECC_vli_sub(result, left, right, num_words);
+ uECC_word_t l_borrow = uECC_vli_sub(result, left, right);
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);
+ uECC_vli_add(result, result, mod);
}
}
/* 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)
+ const uECC_word_t *mod)
{
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;
+ const wordcount_t num_words = NUM_ECC_WORDS;
/* 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);
+ uECC_vli_numBits(mod);
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);
+ uECC_vli_clear(mod_multiple);
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);
+ uECC_vli_set(mod_multiple + word_shift, mod);
}
for (index = 1; shift >= 0; --shift) {
@@ -364,101 +480,97 @@
}
/* Swap the index if there was no borrow */
index = !(index ^ borrow);
- uECC_vli_rshift1(mod_multiple, num_words);
+ uECC_vli_rshift1(mod_multiple);
mod_multiple[num_words - 1] |= mod_multiple[num_words] <<
(uECC_WORD_BITS - 1);
- uECC_vli_rshift1(mod_multiple + num_words, num_words);
+ uECC_vli_rshift1(mod_multiple + num_words);
}
- uECC_vli_set(result, v[index], num_words);
+ uECC_vli_set(result, v[index]);
}
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)
+ const uECC_word_t *right, const uECC_word_t *mod)
{
uECC_word_t product[2 * NUM_ECC_WORDS];
- uECC_vli_mult(product, left, right, num_words);
- uECC_vli_mmod(result, product, mod, num_words);
+ uECC_vli_mult_rnd(product, left, right, NULL);
+ uECC_vli_mmod(result, product, mod);
+}
+
+static void uECC_vli_modMult_rnd(uECC_word_t *result, const uECC_word_t *left,
+ const uECC_word_t *right, ecc_wait_state_t *s)
+{
+ uECC_word_t product[2 * NUM_ECC_WORDS];
+ uECC_vli_mult_rnd(product, left, right, s);
+
+ vli_mmod_fast_secp256r1(result, product);
}
void uECC_vli_modMult_fast(uECC_word_t *result, const uECC_word_t *left,
- const uECC_word_t *right, uECC_Curve curve)
+ const uECC_word_t *right)
{
- uECC_word_t product[2 * NUM_ECC_WORDS];
- uECC_vli_mult(product, left, right, curve->num_words);
-
- curve->mmod_fast(result, product);
+ uECC_vli_modMult_rnd(result, left, right, NULL);
}
-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)
+ const uECC_word_t *mod)
{
uECC_word_t carry = 0;
if (!EVEN(uv)) {
- carry = uECC_vli_add(uv, uv, mod, num_words);
+ carry = uECC_vli_add(uv, uv, mod);
}
- uECC_vli_rshift1(uv, num_words);
+ uECC_vli_rshift1(uv);
if (carry) {
- uv[num_words - 1] |= HIGH_BIT_SET;
+ uv[NUM_ECC_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)
+ const uECC_word_t *mod)
{
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);
+ if (uECC_vli_isZero(input)) {
+ uECC_vli_clear(result);
return;
}
- uECC_vli_set(a, input, num_words);
- uECC_vli_set(b, mod, num_words);
- uECC_vli_clear(u, num_words);
+ uECC_vli_set(a, input);
+ uECC_vli_set(b, mod);
+ uECC_vli_clear(u);
u[0] = 1;
- uECC_vli_clear(v, num_words);
- while ((cmpResult = uECC_vli_cmp_unsafe(a, b, num_words)) != 0) {
+ uECC_vli_clear(v);
+ while ((cmpResult = uECC_vli_cmp_unsafe(a, b)) != 0) {
if (EVEN(a)) {
- uECC_vli_rshift1(a, num_words);
- vli_modInv_update(u, mod, num_words);
+ uECC_vli_rshift1(a);
+ vli_modInv_update(u, mod);
} else if (EVEN(b)) {
- uECC_vli_rshift1(b, num_words);
- vli_modInv_update(v, mod, num_words);
+ uECC_vli_rshift1(b);
+ vli_modInv_update(v, mod);
} 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(a, a, b);
+ uECC_vli_rshift1(a);
+ if (uECC_vli_cmp_unsafe(u, v) < 0) {
+ uECC_vli_add(u, u, mod);
}
- uECC_vli_sub(u, u, v, num_words);
- vli_modInv_update(u, mod, num_words);
+ uECC_vli_sub(u, u, v);
+ vli_modInv_update(u, mod);
} 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(b, b, a);
+ uECC_vli_rshift1(b);
+ if (uECC_vli_cmp_unsafe(v, u) < 0) {
+ uECC_vli_add(v, v, mod);
}
- uECC_vli_sub(v, v, u, num_words);
- vli_modInv_update(v, mod, num_words);
+ uECC_vli_sub(v, v, u);
+ vli_modInv_update(v, mod);
}
}
- uECC_vli_set(result, u, num_words);
+ uECC_vli_set(result, u);
}
/* ------ Point operations ------ */
@@ -471,43 +583,43 @@
uECC_word_t t5[NUM_ECC_WORDS];
wordcount_t num_words = curve->num_words;
- if (uECC_vli_isZero(Z1, num_words)) {
+ if (uECC_vli_isZero(Z1)) {
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_modMult_fast(t4, Y1, Y1); /* t4 = y1^2 */
+ uECC_vli_modMult_fast(t5, X1, t4); /* t5 = x1*y1^2 = A */
+ uECC_vli_modMult_fast(t4, t4, t4); /* t4 = y1^4 */
+ uECC_vli_modMult_fast(Y1, Y1, Z1); /* t2 = y1*z1 = z3 */
+ uECC_vli_modMult_fast(Z1, Z1, Z1); /* 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(X1, X1, Z1, curve->p); /* t1 = x1 + z1^2 */
+ uECC_vli_modAdd(Z1, Z1, Z1, curve->p); /* t3 = 2*z1^2 */
+ uECC_vli_modSub(Z1, X1, Z1, curve->p); /* t3 = x1 - z1^2 */
+ uECC_vli_modMult_fast(X1, X1, Z1); /* 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) */
+ uECC_vli_modAdd(Z1, X1, X1, curve->p); /* t3 = 2*(x1^2 - z1^4) */
+ uECC_vli_modAdd(X1, X1, Z1, curve->p); /* 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);
+ uECC_word_t l_carry = uECC_vli_add(X1, X1, curve->p);
+ uECC_vli_rshift1(X1);
X1[num_words - 1] |= l_carry << (uECC_WORD_BITS - 1);
} else {
- uECC_vli_rshift1(X1, num_words);
+ uECC_vli_rshift1(X1);
}
/* 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) */
+ uECC_vli_modMult_fast(Z1, X1, X1); /* t3 = B^2 */
+ uECC_vli_modSub(Z1, Z1, t5, curve->p); /* t3 = B^2 - A */
+ uECC_vli_modSub(Z1, Z1, t5, curve->p); /* t3 = B^2 - 2A = x3 */
+ uECC_vli_modSub(t5, t5, Z1, curve->p); /* t5 = A - x3 */
+ uECC_vli_modMult_fast(X1, X1, t5); /* t1 = B * (A - x3) */
/* t4 = B * (A - x3) - y1^4 = y3: */
- uECC_vli_modSub(t4, X1, t4, curve->p, num_words);
+ uECC_vli_modSub(t4, X1, t4, curve->p);
- uECC_vli_set(X1, Z1, num_words);
- uECC_vli_set(Z1, Y1, num_words);
- uECC_vli_set(Y1, t4, num_words);
+ uECC_vli_set(X1, Z1);
+ uECC_vli_set(Z1, Y1);
+ uECC_vli_set(Y1, t4);
}
void x_side_default(uECC_word_t *result,
@@ -515,13 +627,12 @@
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 */
+ uECC_vli_modMult_fast(result, x, x); /* r = x^2 */
+ uECC_vli_modSub(result, result, _3, curve->p); /* r = x^2 - 3 */
+ uECC_vli_modMult_fast(result, result, x); /* r = x^3 - 3x */
/* r = x^3 - 3x + b: */
- uECC_vli_modAdd(result, result, curve->b, curve->p, num_words);
+ uECC_vli_modAdd(result, result, curve->b, curve->p);
}
uECC_Curve uECC_secp256r1(void)
@@ -535,7 +646,7 @@
int carry;
/* t */
- uECC_vli_set(result, product, NUM_ECC_WORDS);
+ uECC_vli_set(result, product);
/* s1 */
tmp[0] = tmp[1] = tmp[2] = 0;
@@ -544,8 +655,8 @@
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);
+ carry = uECC_vli_add(tmp, tmp, tmp);
+ carry += uECC_vli_add(result, result, tmp);
/* s2 */
tmp[3] = product[12];
@@ -553,8 +664,8 @@
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);
+ carry += uECC_vli_add(tmp, tmp, tmp);
+ carry += uECC_vli_add(result, result, tmp);
/* s3 */
tmp[0] = product[8];
@@ -563,7 +674,7 @@
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);
+ carry += uECC_vli_add(result, result, tmp);
/* s4 */
tmp[0] = product[9];
@@ -574,7 +685,7 @@
tmp[5] = product[15];
tmp[6] = product[13];
tmp[7] = product[8];
- carry += uECC_vli_add(result, result, tmp, NUM_ECC_WORDS);
+ carry += uECC_vli_add(result, result, tmp);
/* d1 */
tmp[0] = product[11];
@@ -583,7 +694,7 @@
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);
+ carry -= uECC_vli_sub(result, result, tmp);
/* d2 */
tmp[0] = product[12];
@@ -593,7 +704,7 @@
tmp[4] = tmp[5] = 0;
tmp[6] = product[9];
tmp[7] = product[11];
- carry -= uECC_vli_sub(result, result, tmp, NUM_ECC_WORDS);
+ carry -= uECC_vli_sub(result, result, tmp);
/* d3 */
tmp[0] = product[13];
@@ -604,7 +715,7 @@
tmp[5] = product[10];
tmp[6] = 0;
tmp[7] = product[12];
- carry -= uECC_vli_sub(result, result, tmp, NUM_ECC_WORDS);
+ carry -= uECC_vli_sub(result, result, tmp);
/* d4 */
tmp[0] = product[14];
@@ -615,35 +726,35 @@
tmp[5] = product[11];
tmp[6] = 0;
tmp[7] = product[13];
- carry -= uECC_vli_sub(result, result, tmp, NUM_ECC_WORDS);
+ carry -= uECC_vli_sub(result, result, tmp);
if (carry < 0) {
do {
- carry += uECC_vli_add(result, result, curve_secp256r1.p, NUM_ECC_WORDS);
+ carry += uECC_vli_add(result, result, curve_secp256r1.p);
}
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_vli_cmp_unsafe(curve_secp256r1.p, result) != 1) {
+ carry -= uECC_vli_sub(result, result, curve_secp256r1.p);
}
}
}
uECC_word_t EccPoint_isZero(const uECC_word_t *point, uECC_Curve curve)
{
- return uECC_vli_isZero(point, curve->num_words * 2);
+ (void) curve;
+ return uECC_vli_isZero(point);
}
-void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z,
- uECC_Curve curve)
+void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z)
{
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 */
+ uECC_vli_modMult_fast(t1, Z, Z); /* z^2 */
+ uECC_vli_modMult_fast(X1, X1, t1); /* x1 * z^2 */
+ uECC_vli_modMult_fast(t1, t1, Z); /* z^3 */
+ uECC_vli_modMult_fast(Y1, Y1, t1); /* y1 * z^3 */
}
/* P = (x1, y1) => 2P, (x2, y2) => P' */
@@ -653,94 +764,100 @@
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);
+ uECC_vli_set(z, initial_Z);
} else {
- uECC_vli_clear(z, num_words);
+ uECC_vli_clear(z);
z[0] = 1;
}
- uECC_vli_set(X2, X1, num_words);
- uECC_vli_set(Y2, Y1, num_words);
+ uECC_vli_set(X2, X1);
+ uECC_vli_set(Y2, Y1);
- apply_z(X1, Y1, z, curve);
+ apply_z(X1, Y1, z);
curve->double_jacobian(X1, Y1, z, curve);
- apply_z(X2, Y2, z, curve);
+ apply_z(X2, Y2, z);
+}
+
+static void XYcZ_add_rnd(uECC_word_t * X1, uECC_word_t * Y1,
+ uECC_word_t * X2, uECC_word_t * Y2,
+ ecc_wait_state_t *s)
+{
+ /* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
+ uECC_word_t t5[NUM_ECC_WORDS];
+ const uECC_Curve curve = &curve_secp256r1;
+
+ uECC_vli_modSub(t5, X2, X1, curve->p); /* t5 = x2 - x1 */
+ uECC_vli_modMult_rnd(t5, t5, t5, s); /* t5 = (x2 - x1)^2 = A */
+ uECC_vli_modMult_rnd(X1, X1, t5, s); /* t1 = x1*A = B */
+ uECC_vli_modMult_rnd(X2, X2, t5, s); /* t3 = x2*A = C */
+ uECC_vli_modSub(Y2, Y2, Y1, curve->p); /* t4 = y2 - y1 */
+ uECC_vli_modMult_rnd(t5, Y2, Y2, s); /* t5 = (y2 - y1)^2 = D */
+
+ uECC_vli_modSub(t5, t5, X1, curve->p); /* t5 = D - B */
+ uECC_vli_modSub(t5, t5, X2, curve->p); /* t5 = D - B - C = x3 */
+ uECC_vli_modSub(X2, X2, X1, curve->p); /* t3 = C - B */
+ uECC_vli_modMult_rnd(Y1, Y1, X2, s); /* t2 = y1*(C - B) */
+ uECC_vli_modSub(X2, X1, t5, curve->p); /* t3 = B - x3 */
+ uECC_vli_modMult_rnd(Y2, Y2, X2, s); /* t4 = (y2 - y1)*(B - x3) */
+ uECC_vli_modSub(Y2, Y2, Y1, curve->p); /* t4 = y3 */
+
+ uECC_vli_set(X2, t5);
}
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);
+ (void) curve;
+ XYcZ_add_rnd(X1, Y1, X2, Y2, NULL);
}
/* 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)
+static void XYcZ_addC_rnd(uECC_word_t * X1, uECC_word_t * Y1,
+ uECC_word_t * X2, uECC_word_t * Y2,
+ ecc_wait_state_t *s)
{
/* 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;
+ const uECC_Curve curve = &curve_secp256r1;
- 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(t5, X2, X1, curve->p); /* t5 = x2 - x1 */
+ uECC_vli_modMult_rnd(t5, t5, t5, s); /* t5 = (x2 - x1)^2 = A */
+ uECC_vli_modMult_rnd(X1, X1, t5, s); /* t1 = x1*A = B */
+ uECC_vli_modMult_rnd(X2, X2, t5, s); /* t3 = x2*A = C */
+ uECC_vli_modAdd(t5, Y2, Y1, curve->p); /* t5 = y2 + y1 */
+ uECC_vli_modSub(Y2, Y2, Y1, curve->p); /* 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(t6, X2, X1, curve->p); /* t6 = C - B */
+ uECC_vli_modMult_rnd(Y1, Y1, t6, s); /* t2 = y1 * (C - B) = E */
+ uECC_vli_modAdd(t6, X1, X2, curve->p); /* t6 = B + C */
+ uECC_vli_modMult_rnd(X2, Y2, Y2, s); /* t3 = (y2 - y1)^2 = D */
+ uECC_vli_modSub(X2, X2, t6, curve->p); /* 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) */
+ uECC_vli_modSub(t7, X1, X2, curve->p); /* t7 = B - x3 */
+ uECC_vli_modMult_rnd(Y2, Y2, t7, s); /* t4 = (y2 - y1)*(B - x3) */
/* t4 = (y2 - y1)*(B - x3) - E = y3: */
- uECC_vli_modSub(Y2, Y2, Y1, curve->p, num_words);
+ uECC_vli_modSub(Y2, Y2, Y1, curve->p);
- 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) */
+ uECC_vli_modMult_rnd(t7, t5, t5, s); /* t7 = (y2 + y1)^2 = F */
+ uECC_vli_modSub(t7, t7, t6, curve->p); /* t7 = F - (B + C) = x3' */
+ uECC_vli_modSub(t6, t7, X1, curve->p); /* t6 = x3' - B */
+ uECC_vli_modMult_rnd(t6, t6, t5, s); /* t6 = (y2+y1)*(x3' - B) */
/* t2 = (y2+y1)*(x3' - B) - E = y3': */
- uECC_vli_modSub(Y1, t6, Y1, curve->p, num_words);
+ uECC_vli_modSub(Y1, t6, Y1, curve->p);
- uECC_vli_set(X1, t7, num_words);
+ uECC_vli_set(X1, t7);
}
-void EccPoint_mult(uECC_word_t * result, const uECC_word_t * point,
+static 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)
+ const uECC_word_t * initial_Z)
{
/* R0 and R1 */
uECC_word_t Rx[2][NUM_ECC_WORDS];
@@ -748,57 +865,103 @@
uECC_word_t z[NUM_ECC_WORDS];
bitcount_t i;
uECC_word_t nb;
- wordcount_t num_words = curve->num_words;
+ const wordcount_t num_words = NUM_ECC_WORDS;
+ const bitcount_t num_bits = NUM_ECC_BITS + 1; /* from regularize_k */
+ const uECC_Curve curve = uECC_secp256r1();
+ ecc_wait_state_t wait_state;
+ ecc_wait_state_t * const ws = g_rng_function ? &wait_state : NULL;
- uECC_vli_set(Rx[1], point, num_words);
- uECC_vli_set(Ry[1], point + num_words, num_words);
+ uECC_vli_set(Rx[1], point);
+ uECC_vli_set(Ry[1], point + num_words);
XYcZ_initial_double(Rx[1], Ry[1], Rx[0], Ry[0], initial_Z, curve);
for (i = num_bits - 2; i > 0; --i) {
+ ecc_wait_state_reset(ws);
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);
+ XYcZ_addC_rnd(Rx[1 - nb], Ry[1 - nb], Rx[nb], Ry[nb], ws);
+ XYcZ_add_rnd(Rx[nb], Ry[nb], Rx[1 - nb], Ry[1 - nb], ws);
}
+ ecc_wait_state_reset(ws);
nb = !uECC_vli_testBit(scalar, 0);
- XYcZ_addC(Rx[1 - nb], Ry[1 - nb], Rx[nb], Ry[nb], curve);
+ XYcZ_addC_rnd(Rx[1 - nb], Ry[1 - nb], Rx[nb], Ry[nb], ws);
/* 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))*/
+ uECC_vli_modSub(z, Rx[1], Rx[0], curve->p); /* X1 - X0 */
+ uECC_vli_modMult_fast(z, z, Ry[1 - nb]); /* Yb * (X1 - X0) */
+ uECC_vli_modMult_fast(z, z, point); /* xP * Yb * (X1 - X0) */
+ uECC_vli_modInv(z, z, curve->p); /* 1 / (xP * Yb * (X1 - X0))*/
/* yP / (xP * Yb * (X1 - X0)) */
- uECC_vli_modMult_fast(z, z, point + num_words, curve);
+ uECC_vli_modMult_fast(z, z, point + num_words);
/* Xb * yP / (xP * Yb * (X1 - X0)) */
- uECC_vli_modMult_fast(z, z, Rx[1 - nb], curve);
+ uECC_vli_modMult_fast(z, z, Rx[1 - nb]);
/* 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);
+ XYcZ_add_rnd(Rx[nb], Ry[nb], Rx[1 - nb], Ry[1 - nb], ws);
+ apply_z(Rx[0], Ry[0], z);
- uECC_vli_set(result, Rx[0], num_words);
- uECC_vli_set(result + num_words, Ry[0], num_words);
+ uECC_vli_set(result, Rx[0]);
+ uECC_vli_set(result + num_words, Ry[0]);
}
-uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0,
- uECC_word_t *k1, uECC_Curve curve)
+static uECC_word_t regularize_k(const uECC_word_t * const k, uECC_word_t *k0,
+ uECC_word_t *k1)
{
- wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+ wordcount_t num_n_words = NUM_ECC_WORDS;
+ bitcount_t num_n_bits = NUM_ECC_BITS;
+ const uECC_Curve curve = uECC_secp256r1();
- bitcount_t num_n_bits = curve->num_n_bits;
-
- uECC_word_t carry = uECC_vli_add(k0, k, curve->n, num_n_words) ||
+ 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, num_n_words);
+ uECC_vli_add(k1, k0, curve->n);
return carry;
}
+int EccPoint_mult_safer(uECC_word_t * result, const uECC_word_t * point,
+ const uECC_word_t * scalar, uECC_Curve curve)
+{
+ uECC_word_t tmp[NUM_ECC_WORDS];
+ uECC_word_t s[NUM_ECC_WORDS];
+ uECC_word_t *k2[2] = {tmp, s};
+ wordcount_t num_words = NUM_ECC_WORDS;
+ uECC_word_t carry;
+ uECC_word_t *initial_Z = 0;
+ int r;
+
+ if (curve != uECC_secp256r1())
+ return 0;
+
+ /* 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(scalar, tmp, s);
+
+ /* If an RNG function was specified, get a random initial Z value to
+ * protect against side-channel attacks such as Template SPA */
+ if (g_rng_function) {
+ if (!uECC_generate_random_int(k2[carry], curve->p, num_words)) {
+ r = 0;
+ goto clear_and_out;
+ }
+ initial_Z = k2[carry];
+ }
+
+ EccPoint_mult(result, point, k2[!carry], initial_Z);
+ r = 1;
+
+clear_and_out:
+ /* erasing temporary buffer used to store secret: */
+ mbedtls_platform_zeroize(k2, sizeof(k2));
+ mbedtls_platform_zeroize(tmp, sizeof(tmp));
+ mbedtls_platform_zeroize(s, sizeof(s));
+
+ return r;
+}
+
uECC_word_t EccPoint_compute_public_key(uECC_word_t *result,
uECC_word_t *private_key,
uECC_Curve curve)
@@ -809,11 +972,14 @@
uECC_word_t *p2[2] = {tmp1, tmp2};
uECC_word_t carry;
+ if (curve != uECC_secp256r1())
+ return 0;
+
/* 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);
+ carry = regularize_k(private_key, tmp1, tmp2);
- EccPoint_mult(result, curve->G, p2[!carry], 0, curve->num_n_bits + 1, curve);
+ EccPoint_mult(result, curve->G, p2[!carry], 0);
if (EccPoint_isZero(result, curve)) {
return 0;
@@ -837,7 +1003,7 @@
int num_bytes)
{
wordcount_t i;
- uECC_vli_clear(native, (num_bytes + (uECC_WORD_SIZE - 1)) / uECC_WORD_SIZE);
+ uECC_vli_clear(native);
for (i = 0; i < num_bytes; ++i) {
unsigned b = num_bytes - 1 - i;
native[b / uECC_WORD_SIZE] |=
@@ -850,7 +1016,7 @@
{
uECC_word_t mask = (uECC_word_t)-1;
uECC_word_t tries;
- bitcount_t num_bits = uECC_vli_numBits(top, num_words);
+ bitcount_t num_bits = uECC_vli_numBits(top);
if (!g_rng_function) {
return 0;
@@ -862,8 +1028,8 @@
}
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) {
+ if (!uECC_vli_isZero(random) &&
+ uECC_vli_cmp(top, random) == 1) {
return 1;
}
}
@@ -883,16 +1049,16 @@
}
/* 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) {
+ if (uECC_vli_cmp_unsafe(curve->p, point) != 1 ||
+ uECC_vli_cmp_unsafe(curve->p, point + num_words) != 1) {
return -2;
}
- uECC_vli_modSquare_fast(tmp1, point + num_words, curve);
+ uECC_vli_modMult_fast(tmp1, point + num_words, point + num_words);
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)
+ if (uECC_vli_equal(tmp1, tmp2) != 0)
return -3;
return 0;
@@ -909,7 +1075,7 @@
public_key + curve->num_bytes,
curve->num_bytes);
- if (uECC_vli_cmp_unsafe(_public, curve->G, NUM_ECC_WORDS * 2) == 0) {
+ if (memcmp(_public, curve->G, NUM_ECC_WORDS * 2) == 0) {
return -4;
}
@@ -929,11 +1095,11 @@
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))) {
+ if (uECC_vli_isZero(_private)) {
return 0;
}
- if (uECC_vli_cmp(curve->n, _private, BITS_TO_WORDS(curve->num_n_bits)) != 1) {
+ if (uECC_vli_cmp(curve->n, _private) != 1) {
return 0;
}
diff --git a/tinycrypt/ecc_dh.c b/tinycrypt/ecc_dh.c
index 8199210..f9c0a5e 100644
--- a/tinycrypt/ecc_dh.c
+++ b/tinycrypt/ecc_dh.c
@@ -72,12 +72,6 @@
#include <string.h>
#include "mbedtls/platform_util.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)
{
@@ -129,7 +123,7 @@
}
/* 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));
+ uECC_vli_mmod(_private, _random, curve->n);
/* Computing public-key from private: */
if (EccPoint_compute_public_key(_public, _private, curve)) {
@@ -160,15 +154,16 @@
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;
+ /* Protect against invalid curve attacks */
+ if (uECC_valid_public_key(public_key, curve) != 0) {
+ r = 0;
+ goto clear_and_out;
+ }
+
/* Converting buffers to correct bit order: */
uECC_vli_bytesToNative(_private,
private_key,
@@ -180,30 +175,15 @@
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);
+ r = EccPoint_mult_safer(_public, _public, _private, curve);
+ if (r == 0)
+ goto clear_and_out;
uECC_vli_nativeToBytes(secret, num_bytes, _public);
r = !EccPoint_isZero(_public, curve);
clear_and_out:
/* erasing temporary buffer used to store secret: */
- mbedtls_platform_zeroize(p2, sizeof(p2));
- mbedtls_platform_zeroize(tmp, sizeof(tmp));
mbedtls_platform_zeroize(_private, sizeof(_private));
return r;
diff --git a/tinycrypt/ecc_dsa.c b/tinycrypt/ecc_dsa.c
index a3893d3..04b1bfa 100644
--- a/tinycrypt/ecc_dsa.c
+++ b/tinycrypt/ecc_dsa.c
@@ -87,7 +87,7 @@
bits_size = num_n_bytes;
}
- uECC_vli_clear(native, num_n_words);
+ uECC_vli_clear(native);
uECC_vli_bytesToNative(native, bits, bits_size);
if (bits_size * 8 <= (unsigned)curve->num_n_bits) {
return;
@@ -102,8 +102,8 @@
}
/* 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);
+ if (uECC_vli_cmp_unsafe(curve->n, native) != 1) {
+ uECC_vli_sub(native, native, curve->n);
}
}
@@ -114,29 +114,26 @@
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;
+ int r;
+
/* Make sure 0 < k < curve_n */
- if (uECC_vli_isZero(k, num_words) ||
- uECC_vli_cmp(curve->n, k, num_n_words) != 1) {
+ if (uECC_vli_isZero(k) ||
+ uECC_vli_cmp(curve->n, k) != 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)) {
+ r = EccPoint_mult_safer(p, curve->G, k, curve);
+ if (r == 0 || uECC_vli_isZero(p)) {
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);
+ uECC_vli_clear(tmp);
tmp[0] = 1;
}
else if (!uECC_generate_random_int(tmp, curve->n, num_n_words)) {
@@ -145,9 +142,9 @@
/* 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_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, curve->num_bytes, p); /* store r */
@@ -155,13 +152,13 @@
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 */
+ uECC_vli_set(s, p);
+ 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, 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) {
+ 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)curve->num_bytes * 8) {
return 0;
}
@@ -185,7 +182,7 @@
}
// 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));
+ uECC_vli_mmod(k, _random, curve->n);
if (uECC_sign_with_k(private_key, message_hash, hash_size, k, signature,
curve)) {
@@ -223,6 +220,9 @@
wordcount_t num_words = curve->num_words;
wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
+ if (curve != uECC_secp256r1())
+ return 0;
+
rx[num_n_words - 1] = 0;
r[num_n_words - 1] = 0;
s[num_n_words - 1] = 0;
@@ -234,46 +234,46 @@
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)) {
+ if (uECC_vli_isZero(r) || uECC_vli_isZero(s)) {
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) {
+ if (uECC_vli_cmp_unsafe(curve->n, r) != 1 ||
+ uECC_vli_cmp_unsafe(curve->n, s) != 1) {
return 0;
}
/* Calculate u1 and u2. */
- uECC_vli_modInv(z, s, curve->n, num_n_words); /* 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, num_n_words); /* u1 = e/s */
- uECC_vli_modMult(u2, r, z, curve->n, num_n_words); /* 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, 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 */
+ uECC_vli_set(sum, _public);
+ uECC_vli_set(sum + num_words, _public + num_words);
+ uECC_vli_set(tx, curve->G);
+ uECC_vli_set(ty, curve->G + num_words);
+ uECC_vli_modSub(z, sum, tx, curve->p); /* 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);
+ uECC_vli_modInv(z, z, curve->p); /* z = 1/z */
+ apply_z(sum, sum + num_words, z);
/* 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));
+ num_bits = smax(uECC_vli_numBits(u1),
+ uECC_vli_numBits(u2));
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);
+ uECC_vli_set(rx, point);
+ uECC_vli_set(ry, point + num_words);
+ uECC_vli_clear(z);
z[0] = 1;
for (i = num_bits - 2; i >= 0; --i) {
@@ -283,25 +283,25 @@
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 */
+ uECC_vli_set(tx, point);
+ uECC_vli_set(ty, point + num_words);
+ apply_z(tx, ty, z);
+ uECC_vli_modSub(tz, rx, tx, curve->p); /* Z = x2 - x1 */
XYcZ_add(tx, ty, rx, ry, curve);
- uECC_vli_modMult_fast(z, z, tz, curve);
+ uECC_vli_modMult_fast(z, z, tz);
}
}
- uECC_vli_modInv(z, z, curve->p, num_words); /* Z = 1/Z */
- apply_z(rx, ry, z, curve);
+ uECC_vli_modInv(z, z, curve->p); /* Z = 1/Z */
+ apply_z(rx, ry, z);
/* 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);
+ if (uECC_vli_cmp_unsafe(curve->n, rx) != 1) {
+ uECC_vli_sub(rx, rx, curve->n);
}
/* Accept only if v == r. */
- return (int)(uECC_vli_equal(rx, r, num_words) == 0);
+ return (int)(uECC_vli_equal(rx, r) == 0);
}
#else
typedef int mbedtls_dummy_tinycrypt_def;