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comparison rsa_make_key.c @ 3:7faae8f46238 libtomcrypt-orig

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Branch renaming
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:41 +0000
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children 6362d3854bb4
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-1:000000000000 3:7faae8f46238
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org
10 */
11
12 /* RSA Code by Tom St Denis */
13 #include "mycrypt.h"
14
15 #ifdef MRSA
16
17 int rsa_make_key(prng_state *prng, int wprng, int size, long e, rsa_key *key)
18 {
19 mp_int p, q, tmp1, tmp2, tmp3;
20 int err;
21
22 _ARGCHK(key != NULL);
23
24 if ((size < (MIN_RSA_SIZE/8)) || (size > (MAX_RSA_SIZE/8))) {
25 return CRYPT_INVALID_KEYSIZE;
26 }
27
28 if ((e < 3) || ((e & 1) == 0)) {
29 return CRYPT_INVALID_ARG;
30 }
31
32 if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
33 return err;
34 }
35
36 if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, &tmp3, NULL)) != MP_OKAY) {
37 return mpi_to_ltc_error(err);
38 }
39
40 /* make primes p and q (optimization provided by Wayne Scott) */
41 if ((err = mp_set_int(&tmp3, e)) != MP_OKAY) { goto error; } /* tmp3 = e */
42
43 /* make prime "p" */
44 do {
45 if ((err = rand_prime(&p, size*4, prng, wprng)) != CRYPT_OK) { goto done; }
46 if ((err = mp_sub_d(&p, 1, &tmp1)) != MP_OKAY) { goto error; } /* tmp1 = p-1 */
47 if ((err = mp_gcd(&tmp1, &tmp3, &tmp2)) != MP_OKAY) { goto error; } /* tmp2 = gcd(p-1, e) */
48 } while (mp_cmp_d(&tmp2, 1) != 0); /* while e divides p-1 */
49
50 /* make prime "q" */
51 do {
52 if ((err = rand_prime(&q, size*4, prng, wprng)) != CRYPT_OK) { goto done; }
53 if ((err = mp_sub_d(&q, 1, &tmp1)) != MP_OKAY) { goto error; } /* tmp1 = q-1 */
54 if ((err = mp_gcd(&tmp1, &tmp3, &tmp2)) != MP_OKAY) { goto error; } /* tmp2 = gcd(q-1, e) */
55 } while (mp_cmp_d(&tmp2, 1) != 0); /* while e divides q-1 */
56
57 /* tmp1 = lcm(p-1, q-1) */
58 if ((err = mp_sub_d(&p, 1, &tmp2)) != MP_OKAY) { goto error; } /* tmp2 = p-1 */
59 /* tmp1 = q-1 (previous do/while loop) */
60 if ((err = mp_lcm(&tmp1, &tmp2, &tmp1)) != MP_OKAY) { goto error; } /* tmp1 = lcm(p-1, q-1) */
61
62 /* make key */
63 if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP,
64 &key->qP, &key->pQ, &key->p, &key->q, NULL)) != MP_OKAY) {
65 goto error;
66 }
67
68 if ((err = mp_set_int(&key->e, e)) != MP_OKAY) { goto error2; } /* key->e = e */
69 if ((err = mp_invmod(&key->e, &tmp1, &key->d)) != MP_OKAY) { goto error2; } /* key->d = 1/e mod lcm(p-1,q-1) */
70 if ((err = mp_mul(&p, &q, &key->N)) != MP_OKAY) { goto error2; } /* key->N = pq */
71
72 /* optimize for CRT now */
73 /* find d mod q-1 and d mod p-1 */
74 if ((err = mp_sub_d(&p, 1, &tmp1)) != MP_OKAY) { goto error2; } /* tmp1 = q-1 */
75 if ((err = mp_sub_d(&q, 1, &tmp2)) != MP_OKAY) { goto error2; } /* tmp2 = p-1 */
76
77 if ((err = mp_mod(&key->d, &tmp1, &key->dP)) != MP_OKAY) { goto error2; } /* dP = d mod p-1 */
78 if ((err = mp_mod(&key->d, &tmp2, &key->dQ)) != MP_OKAY) { goto error2; } /* dQ = d mod q-1 */
79
80 if ((err = mp_invmod(&q, &p, &key->qP)) != MP_OKAY) { goto error2; } /* qP = 1/q mod p */
81 if ((err = mp_mulmod(&key->qP, &q, &key->N, &key->qP)) != MP_OKAY) { goto error2; } /* qP = q * (1/q mod p) mod N */
82
83 if ((err = mp_invmod(&p, &q, &key->pQ)) != MP_OKAY) { goto error2; } /* pQ = 1/p mod q */
84 if ((err = mp_mulmod(&key->pQ, &p, &key->N, &key->pQ)) != MP_OKAY) { goto error2; } /* pQ = p * (1/p mod q) mod N */
85
86 if ((err = mp_copy(&p, &key->p)) != MP_OKAY) { goto error2; }
87 if ((err = mp_copy(&q, &key->q)) != MP_OKAY) { goto error2; }
88
89 /* shrink ram required */
90 if ((err = mp_shrink(&key->e)) != MP_OKAY) { goto error2; }
91 if ((err = mp_shrink(&key->d)) != MP_OKAY) { goto error2; }
92 if ((err = mp_shrink(&key->N)) != MP_OKAY) { goto error2; }
93 if ((err = mp_shrink(&key->dQ)) != MP_OKAY) { goto error2; }
94 if ((err = mp_shrink(&key->dP)) != MP_OKAY) { goto error2; }
95 if ((err = mp_shrink(&key->qP)) != MP_OKAY) { goto error2; }
96 if ((err = mp_shrink(&key->pQ)) != MP_OKAY) { goto error2; }
97 if ((err = mp_shrink(&key->p)) != MP_OKAY) { goto error2; }
98 if ((err = mp_shrink(&key->q)) != MP_OKAY) { goto error2; }
99
100 err = CRYPT_OK;
101 key->type = PK_PRIVATE_OPTIMIZED;
102 goto done;
103 error2:
104 mp_clear_multi(&key->d, &key->e, &key->N, &key->dQ, &key->dP,
105 &key->qP, &key->pQ, &key->p, &key->q, NULL);
106 error:
107 err = mpi_to_ltc_error(err);
108 done:
109 mp_clear_multi(&tmp3, &tmp2, &tmp1, &p, &q, NULL);
110 return err;
111 }
112
113 #endif