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Improve speed of mp_rand

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This commit is contained in:
Sean Parkinson
2019-12-20 12:20:50 +10:00
parent 7d2adb2fc0
commit 75637445ee
2 changed files with 43 additions and 30 deletions
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70
wolfcrypt/src/wolfmath.c
View File

@@ -99,46 +99,56 @@ int get_rand_digit(WC_RNG* rng, mp_digit* d)
int mp_rand(mp_int* a, int digits, WC_RNG* rng)
{
int ret = 0;
mp_digit d;
int cnt = digits * sizeof(mp_digit);
#if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
int i;
#endif
if (rng == NULL) {
ret = MISSING_RNG_E; goto exit;
ret = MISSING_RNG_E;
}
else if (a == NULL) {
ret = BAD_FUNC_ARG;
}
if (a == NULL) {
ret = BAD_FUNC_ARG; goto exit;
#if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
/* allocate space for digits */
if (ret == MP_OKAY) {
ret = mp_set_bit(a, digits * DIGIT_BIT - 1);
}
mp_zero(a);
if (digits <= 0) {
ret = MP_OKAY; goto exit;
#else
#if defined(USE_FAST_MATH)
if ((ret == MP_OKAY) && (digits > FP_SIZE))
#else
if ((ret == MP_OKAY) && (digits > SP_INT_DIGITS))
#endif
{
ret = BAD_FUNC_ARG;
}
/* first place a random non-zero digit */
do {
ret = get_rand_digit(rng, &d);
if (ret != 0) {
goto exit;
if (ret == MP_OKAY) {
a->used = digits;
}
#endif
/* fill the data with random bytes */
if (ret == MP_OKAY) {
ret = wc_RNG_GenerateBlock(rng, (byte*)a->dp, cnt);
}
if (ret == MP_OKAY) {
#if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
/* Mask down each digit to only bits used */
for (i = 0; i < a->used; i++) {
a->dp[i] &= MP_MASK;
}
} while (d == 0);
if ((ret = mp_add_d(a, d, a)) != MP_OKAY) {
goto exit;
}
while (--digits > 0) {
if ((ret = mp_lshd(a, 1)) != MP_OKAY) {
goto exit;
}
if ((ret = get_rand_digit(rng, &d)) != 0) {
goto exit;
}
if ((ret = mp_add_d(a, d, a)) != MP_OKAY) {
goto exit;
#endif
/* ensure top digit is not zero */
while ((ret == MP_OKAY) && (a->dp[a->used - 1] == 0)) {
ret = get_rand_digit(rng, &a->dp[a->used - 1]);
#if !defined(USE_FAST_MATH) && !defined(WOLFSSL_SP_MATH)
a->dp[a->used - 1] &= MP_MASK;
#endif
}
}
exit:
return ret;
}
#endif /* WC_RSA_BLINDING */

3
wolfssl/wolfcrypt/sp_int.h
View File

@@ -102,6 +102,8 @@
#endif
#endif
#define SP_MASK (sp_digit)(-1)
#ifdef WOLFSSL_SP_MATH
#include <wolfssl/wolfcrypt/random.h>
@@ -219,6 +221,7 @@ MP_API void sp_rshb(sp_int* a, int n, sp_int* r);
#define MP_VAL -3
#define DIGIT_BIT SP_WORD_SIZE
#define MP_MASK SP_MASK
#define CheckFastMathSettings() 1