diff options
| -rw-r--r-- | cryptech.h | 8 | ||||
| -rw-r--r-- | rsa.c | 96 | ||||
| -rw-r--r-- | tests/test-rsa.c | 3 |
3 files changed, 103 insertions, 4 deletions
@@ -609,7 +609,7 @@ extern void hal_rsa_set_debug(const int onoff); extern const size_t hal_rsa_key_t_size; -typedef enum { RSA_PRIVATE, RSA_PUBLIC } hal_rsa_key_type_t; +typedef enum { HAL_RSA_PRIVATE, HAL_RSA_PUBLIC } hal_rsa_key_type_t; typedef struct { void *key; } hal_rsa_key_t; @@ -631,6 +631,12 @@ extern hal_error_t hal_rsa_crt(hal_rsa_key_t key, const uint8_t * const m, const size_t m_len, uint8_t * result, const size_t result_len); +extern hal_error_t hal_rsa_gen(hal_rsa_key_t *key, + void *keybuf, const size_t keybuf_len, + const unsigned key_length, + const unsigned long public_exponent); + + #endif /* _CRYPTECH_H_ */ /* @@ -241,9 +241,9 @@ hal_error_t hal_rsa_key_load(const hal_rsa_key_type_t type, #define _(x) do { fp_init(&key->x); if (x == NULL) goto fail; fp_read_unsigned_bin(&key->x, (uint8_t *) x, x##_len); } while (0) switch (type) { - case RSA_PRIVATE: + case HAL_RSA_PRIVATE: _(d); _(p); _(q); _(u); _(dP); _(dQ); - case RSA_PUBLIC: + case HAL_RSA_PUBLIC: _(n); _(e); key_->key = key; return HAL_OK; @@ -317,6 +317,98 @@ hal_error_t hal_rsa_crt(hal_rsa_key_t key_, return err; } +static hal_error_t find_prime(unsigned prime_length, fp_int *e, fp_int *result) +{ + uint8_t buffer[prime_length]; + hal_error_t err; + fp_int t; + + /* + * Get random bytes, munge a few bits, and stuff into a bignum. + * Keep doing this until we find a result that's (probably) prime + * and for which result - 1 is relatively prime with respect to e. + */ + + do { + if ((err = hal_get_random(buffer, sizeof(buffer))) != HAL_OK) + return err; + buffer[0 ] |= 0xc0; + buffer[sizeof(buffer) - 1] |= 0x01; + fp_read_unsigned_bin(result, buffer, sizeof(buffer)); + + } while (!fp_isprime(result) || + (fp_sub_d(result, 1, &t), fp_gcd(&t, e, &t), fp_cmp_d(&t, 1) != FP_EQ)); + + fp_zero(&t); + return HAL_OK; +} + +hal_error_t hal_rsa_gen(hal_rsa_key_t *key_, + void *keybuf, const size_t keybuf_len, + const unsigned key_length, + const unsigned long public_exponent) +{ + struct rsa_key *key = keybuf; + hal_error_t err = HAL_OK; + fp_int p_1, q_1; + + if (key_ == NULL || keybuf == NULL || keybuf_len < sizeof(struct rsa_key)) + return HAL_ERROR_BAD_ARGUMENTS; + + switch (key_length) { + case bitsToBytes(1024): + case bitsToBytes(2048): + case bitsToBytes(4096): + case bitsToBytes(8192): + break; + default: + return HAL_ERROR_UNSUPPORTED_KEY; + } + + switch (public_exponent) { + case 0x010001: + break; + default: + return HAL_ERROR_UNSUPPORTED_KEY; + } + + /* + * Initialize key + */ + + memset(keybuf, 0, keybuf_len); + key->type = HAL_RSA_PRIVATE; + fp_set(&key->e, public_exponent); + + /* + * Find a good pair of prime numbers. + */ + + if ((err = find_prime(key_length / 2, &key->e, &key->p)) != HAL_OK || + (err = find_prime(key_length / 2, &key->e, &key->q)) != HAL_OK) + return err; + + /* + * Calculate remaining key components. + */ + + fp_sub_d(&key->p, 1, &p_1); + fp_sub_d(&key->q, 1, &q_1); + fp_mul(&key->p, &key->q, &key->n); /* n = p * q */ + fp_lcm(&p_1, &q_1, &key->d); + FP_CHECK(fp_invmod(&key->e, &key->d, &key->d)); /* d = (1/e) % lcm(p-1, q-1) */ + FP_CHECK(fp_mod(&key->d, &p_1, &key->dP)); /* dP = d % (p-1) */ + FP_CHECK(fp_mod(&key->d, &q_1, &key->dQ)); /* dQ = d % (q-1) */ + FP_CHECK(fp_invmod(&key->q, &key->p, &key->u)); /* u = (1/q) % p */ + + /* Fall through to cleanup */ + + fail: + fp_zero(&p_1); + fp_zero(&q_1); + return err; +} + /* * Local variables: * indent-tabs-mode: nil diff --git a/tests/test-rsa.c b/tests/test-rsa.c index b415955..707cbe9 100644 --- a/tests/test-rsa.c +++ b/tests/test-rsa.c @@ -89,7 +89,8 @@ static int test_crt(const char * const kind, const rsa_tc_t * const tc) hal_error_t err = HAL_OK; hal_rsa_key_t key; - if ((err = hal_rsa_key_load(RSA_PRIVATE, &key, keybuf, sizeof(keybuf), + if ((err = hal_rsa_key_load(HAL_RSA_PRIVATE, &key, + keybuf, sizeof(keybuf), tc->n.val, tc->n.len, tc->e.val, tc->e.len, tc->d.val, tc->d.len, |