diff options
Diffstat (limited to 'rsa.c')
| -rw-r--r-- | rsa.c | 63 |
1 files changed, 38 insertions, 25 deletions
@@ -78,12 +78,15 @@ #include "asn1_internal.h" /* - * Whether to use ModExp core. It works, but at the moment it's so - * slow that a full test run can take more than an hour. + * Whether to use ModExp core. It works, but it's painfully slow. */ -#ifndef HAL_RSA_USE_MODEXP -#define HAL_RSA_USE_MODEXP 1 +#ifndef HAL_RSA_SIGN_USE_MODEXP +#define HAL_RSA_SIGN_USE_MODEXP 1 +#endif + +#ifndef HAL_RSA_KEYGEN_USE_MODEXP +#define HAL_RSA_KEYGEN_USE_MODEXP 0 #endif #if defined(RPC_CLIENT) && RPC_CLIENT != RPC_CLIENT_LOCAL @@ -182,7 +185,7 @@ static hal_error_t unpack_fp(const fp_int * const bn, uint8_t *buffer, const siz return err; } -#if HAL_RSA_USE_MODEXP +#if HAL_RSA_SIGN_USE_MODEXP /* * Unwrap bignums into byte arrays, feed them into hal_modexp(), and @@ -236,27 +239,13 @@ static hal_error_t modexp(hal_core_t *core, return err; } -/* - * Wrapper to let us export our modexp function as a replacement for - * TFM's, to avoid dragging in all of the TFM montgomery code when we - * use TFM's Miller-Rabin test code. - * - * This code is here rather than in a separate module because of the - * error handling: TFM's error codes aren't really capable of - * expressing all the things that could go wrong here. - */ - -int fp_exptmod(fp_int *a, fp_int *b, fp_int *c, fp_int *d) -{ - return modexp(NULL, a, b, c, d) == HAL_OK ? FP_OKAY : FP_VAL; -} - -#else /* HAL_RSA_USE_MODEXP */ +#else /* HAL_RSA_SIGN_USE_MODEXP */ /* - * Workaround to let us use TFM's software implementation of modular - * exponentiation when we want to test other things and don't want to - * wait for the slow FPGA implementation. + * Use libtfm's software implementation of modular exponentiation. + * Now that the ModExpA7 core performs about as well as the software + * implementation, there's probably no need to use this, but we're + * still tuning things, so leave the hook here for now. */ static hal_error_t modexp(const hal_core_t *core, /* ignored */ @@ -271,7 +260,31 @@ static hal_error_t modexp(const hal_core_t *core, /* ignored */ return err; } -#endif /* HAL_RSA_USE_MODEXP */ +#endif /* HAL_RSA_SIGN_USE_MODEXP */ + +/* + * Wrapper to let us export our modexp function as a replacement for + * libtfm's when running libtfm's Miller-Rabin test code. + * + * At the moment, the libtfm software implementation performs + * disproportionately better than our core does for the specific case + * of Miller-Rabin tests, for reasons we don't really understand. + * So there's not much point in enabling this, except as a test to + * confirm this behavior. + * + * This code is here rather than in a separate module because of the + * error handling: libtfm's error codes aren't really capable of + * expressing all the things that could go wrong here. + */ + +#if HAL_RSA_SIGN_USE_MODEXP && HAL_RSA_KEYGEN_USE_MODEXP + +int fp_exptmod(fp_int *a, fp_int *b, fp_int *c, fp_int *d) +{ + return modexp(NULL, a, b, c, d) == HAL_OK ? FP_OKAY : FP_VAL; +} + +#endif /* HAL_RSA_SIGN_USE_MODEXP && HAL_RSA_KEYGEN_USE_MODEXP */ /* * Create blinding factors. There are various schemes for amortizing |