diff options
Diffstat (limited to 'rsa.c')
| -rw-r--r-- | rsa.c | 29 |
1 files changed, 29 insertions, 0 deletions
@@ -49,6 +49,15 @@ #include "cryptech.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. + */ + +#ifndef HAL_RSA_USE_MODEXP +#define HAL_RSA_USE_MODEXP 1 +#endif + +/* * Use "Tom's Fast Math" library for our bignum implementation. This * particular implementation has a couple of nice features: * @@ -154,6 +163,8 @@ static hal_error_t unpack_fp(fp_int *bn, uint8_t *buffer, const size_t length) return err; } +#if HAL_RSA_USE_MODEXP + /* * Unwrap bignums into byte arrays, feeds them into hal_modexp(), and * wrap result back up as a bignum. @@ -206,6 +217,24 @@ int fp_exptmod(fp_int *a, fp_int *b, fp_int *c, fp_int *d) return modexp(a, b, c, d) == HAL_OK ? FP_OKAY : FP_VAL; } +#else /* HAL_RSA_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. + */ + +static hal_error_t modexp(fp_int *msg, fp_int *exp, fp_int *mod, fp_int *res) +{ + hal_error_t err = HAL_OK; + FP_CHECK(fp_exptmod(msg, exp, mod, res)); + fail: + return err; +} + +#endif /* HAL_RSA_USE_MODEXP */ + /* * Create blinding factors. There are various schemes for amortizing * the cost of this over multiple RSA operations, at present we don't |