int tpm_rsa_import_key(tpm_rsa_private_key_t *key, int endian,
const uint8_t *n, size_t n_len,
const uint8_t *e, size_t e_len,
const uint8_t *p, const uint8_t *q)
{
tpm_bn_t t1, t2, phi;
if (n == NULL || n_len == 0 || (p == NULL && q == NULL)) return -1;
/* init key */
key->size = n_len << 3;
if (e == NULL || e_len == 0) {
tpm_bn_init_set_ui(key->e, 65537);
} else {
tpm_bn_init2(key->e, e_len << 3);
tpm_bn_import(key->e, e_len, endian, e);
}
tpm_bn_init2(key->n, key->size);
tpm_bn_init2(key->p, key->size / 2);
tpm_bn_init2(key->q, key->size / 2);
tpm_bn_init2(key->d, key->size);
tpm_bn_init2(key->u, key->size / 2);
tpm_bn_init2(t1, key->size / 2);
tpm_bn_init2(t2, key->size / 2);
tpm_bn_init2(phi, key->size);
/* import values */
tpm_bn_import(key->n, n_len, endian, n);
if (p != NULL) tpm_bn_import(key->p, n_len / 2, endian, p);
if (q != NULL) tpm_bn_import(key->q, n_len / 2, endian, q);
if (p == NULL) tpm_bn_tdiv_q(key->p, key->n, key->q);
if (q == NULL) tpm_bn_tdiv_q(key->q, key->n, key->p);
/* p shall be smaller than q */
if (tpm_bn_cmp(key->p, key->q) > 0) tpm_bn_swap(key->p, key->q);
/* calculate missing values */
tpm_bn_sub_ui(t1, key->p, 1);
tpm_bn_sub_ui(t2, key->q, 1);
tpm_bn_mul(phi, t1, t2);
tpm_bn_invert(key->d, key->e, phi);
tpm_bn_invert(key->u, key->p, key->q);
/* release helper variables */
tpm_bn_clear(t1);
tpm_bn_clear(t2);
tpm_bn_clear(phi);
/* test key */
if (rsa_test_key(key) != 0) {
tpm_rsa_release_private_key(key);
return -1;
}
return 0;
}
int rsa_import_key(rsa_private_key_t *key, int endian,
uint8_t *n, size_t n_len, uint8_t *e, size_t e_len,
uint8_t *p, uint8_t *q)
{
mpz_t t1, t2, phi;
if (n == NULL || n_len == 0 || (p == NULL && q == NULL)) return -1;
/* init key */
key->size = n_len << 3;
if (e == NULL || e_len == 0) {
mpz_init_set_ui(key->e, 65537);
} else {
mpz_init2(key->e, (e_len << 3) + GMP_NUMB_BITS);
mpz_import(key->e, e_len, endian, 1, 0, 0, e);
}
mpz_init2(key->n, key->size + GMP_NUMB_BITS);
mpz_init2(key->p, key->size / 2 + GMP_NUMB_BITS);
mpz_init2(key->q, key->size / 2 + GMP_NUMB_BITS);
mpz_init2(key->d, key->size + GMP_NUMB_BITS);
mpz_init2(key->u, key->size / 2 + GMP_NUMB_BITS);
mpz_init2(t1, key->size / 2 + GMP_NUMB_BITS);
mpz_init2(t2, key->size / 2 + GMP_NUMB_BITS);
mpz_init2(phi, key->size + GMP_NUMB_BITS);
/* import values */
mpz_import(key->n, n_len, endian, 1, 0, 0, n);
if (p != NULL) mpz_import(key->p, n_len / 2, endian, 1, 0, 0, p);
if (q != NULL) mpz_import(key->q, n_len / 2, endian, 1, 0, 0, q);
if (p == NULL) mpz_tdiv_q(key->p, key->n, key->q);
if (q == NULL) mpz_tdiv_q(key->q, key->n, key->p);
/* p shall be smaller than q */
if (mpz_cmp(key->p, key->q) > 0) mpz_swap(key->p, key->q);
/* calculate missing values */
mpz_sub_ui(t1, key->p, 1);
mpz_sub_ui(t2, key->q, 1);
mpz_mul(phi, t1, t2);
mpz_invert(key->d, key->e, phi);
mpz_invert(key->u, key->p, key->q);
/* release helper variables */
mpz_clear(t1);
mpz_clear(t2);
mpz_clear(phi);
/* test key */
if (rsa_test_key(key) != 0) {
rsa_release_private_key(key);
return -1;
}
return 0;
}
int rsa_generate_key(rsa_private_key_t *key, int key_size)
{
mpz_t e, p, q, n, t1, t2, phi, d, u;
/* bit_size must be even */
if (key_size & 0x01) key_size++;
/* we use e = 65537 */
mpz_init_set_ui(e, 65537);
mpz_init2(p, key_size / 2 + GMP_NUMB_BITS);
mpz_init2(q, key_size / 2 + GMP_NUMB_BITS);
mpz_init2(n, key_size + GMP_NUMB_BITS);
mpz_init2(t1, key_size / 2 + GMP_NUMB_BITS);
mpz_init2(t2, key_size / 2 + GMP_NUMB_BITS);
mpz_init2(phi, key_size + GMP_NUMB_BITS);
mpz_init2(d, key_size + GMP_NUMB_BITS);
mpz_init2(u, key_size / 2 + GMP_NUMB_BITS);
do {
/* get prime p */
mpz_urandomb(p, NULL, key_size / 2);
mpz_setbit(p, 0);
mpz_setbit(p, key_size / 2 - 1);
mpz_setbit(p, key_size / 2 - 2);
mpz_nextprime(p, p);
mpz_sub_ui(t1, p, 1);
mpz_gcd(phi, e, t1);
if (mpz_cmp_ui(phi, 1) != 0) continue;
/* get prime q */
mpz_urandomb(q, NULL, key_size / 2);
mpz_setbit(q, 0);
mpz_setbit(q, key_size / 2 - 1);
mpz_setbit(q, key_size / 2 - 2);
mpz_nextprime(q, q);
mpz_sub_ui(t2, q, 1);
mpz_gcd(phi, e, t1);
if (mpz_cmp_ui(phi, 1) != 0) continue;
/* p shall be smaller than q */
if (mpz_cmp(p, q) > 0) mpz_swap(p, q);
/* calculate the modulus */
mpz_mul(n, p, q);
} while (mpz_sizeinbase(n, 2) != key_size);
/* calculate Euler totient: phi = (p-1)(q-1) */
mpz_mul(phi, t1, t2);
/* calculate the secret key d = e^(-1) mod phi */
mpz_invert(d, e, phi);
/* calculate the inverse of p and q (used for chinese remainder theorem) */
mpz_invert(u, p, q);
/* setup private key */
mpz_init_set(key->n, n);
mpz_init_set(key->e, e);
mpz_init_set(key->p, p);
mpz_init_set(key->q, q);
mpz_init_set(key->d, d);
mpz_init_set(key->u, u);
key->size = key_size;
/* release helper variables */
mpz_clear(e);
mpz_clear(p);
mpz_clear(q);
mpz_clear(n);
mpz_clear(t1);
mpz_clear(t2);
mpz_clear(phi);
mpz_clear(d);
mpz_clear(u);
/* test key */
if (rsa_test_key(key) != 0) {
rsa_release_private_key(key);
return -1;
}
return 0;
}
