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comparison libtomcrypt/src/pk/rsa/rsa_make_key.c @ 399:a707e6148060

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merge of '5fdf69ca60d1683cdd9f4c2595134bed26394834' and '6b61c50f4cf888bea302ac8fcf5dbb573b443251'
author Matt Johnston <matt@ucc.asn.au>
date Sat, 03 Feb 2007 08:20:34 +0000
parents 0cbe8f6dbf9e
children f849a5ca2efc
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394:17d097fc111c 399:a707e6148060
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.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file rsa_make_key.c
15 RSA key generation, Tom St Denis
16 */
17
18 #ifdef MRSA
19
20 /**
21 Create an RSA key
22 @param prng An active PRNG state
23 @param wprng The index of the PRNG desired
24 @param size The size of the modulus (key size) desired (octets)
25 @param e The "e" value (public key). e==65537 is a good choice
26 @param key [out] Destination of a newly created private key pair
27 @return CRYPT_OK if successful, upon error all allocated ram is freed
28 */
29 int rsa_make_key(prng_state *prng, int wprng, int size, long e, rsa_key *key)
30 {
31 void *p, *q, *tmp1, *tmp2, *tmp3;
32 int err;
33
34 LTC_ARGCHK(ltc_mp.name != NULL);
35 LTC_ARGCHK(key != NULL);
36
37 if ((size < (MIN_RSA_SIZE/8)) || (size > (MAX_RSA_SIZE/8))) {
38 return CRYPT_INVALID_KEYSIZE;
39 }
40
41 if ((e < 3) || ((e & 1) == 0)) {
42 return CRYPT_INVALID_ARG;
43 }
44
45 if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
46 return err;
47 }
48
49 if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, &tmp3, NULL)) != CRYPT_OK) {
50 return err;
51 }
52
53 /* make primes p and q (optimization provided by Wayne Scott) */
54 if ((err = mp_set_int(tmp3, e)) != CRYPT_OK) { goto errkey; } /* tmp3 = e */
55
56 /* make prime "p" */
57 do {
58 if ((err = rand_prime( p, size/2, prng, wprng)) != CRYPT_OK) { goto errkey; }
59 if ((err = mp_sub_d( p, 1, tmp1)) != CRYPT_OK) { goto errkey; } /* tmp1 = p-1 */
60 if ((err = mp_gcd( tmp1, tmp3, tmp2)) != CRYPT_OK) { goto errkey; } /* tmp2 = gcd(p-1, e) */
61 } while (mp_cmp_d( tmp2, 1) != 0); /* while e divides p-1 */
62
63 /* make prime "q" */
64 do {
65 if ((err = rand_prime( q, size/2, prng, wprng)) != CRYPT_OK) { goto errkey; }
66 if ((err = mp_sub_d( q, 1, tmp1)) != CRYPT_OK) { goto errkey; } /* tmp1 = q-1 */
67 if ((err = mp_gcd( tmp1, tmp3, tmp2)) != CRYPT_OK) { goto errkey; } /* tmp2 = gcd(q-1, e) */
68 } while (mp_cmp_d( tmp2, 1) != 0); /* while e divides q-1 */
69
70 /* tmp1 = lcm(p-1, q-1) */
71 if ((err = mp_sub_d( p, 1, tmp2)) != CRYPT_OK) { goto errkey; } /* tmp2 = p-1 */
72 /* tmp1 = q-1 (previous do/while loop) */
73 if ((err = mp_lcm( tmp1, tmp2, tmp1)) != CRYPT_OK) { goto errkey; } /* tmp1 = lcm(p-1, q-1) */
74
75 /* make key */
76 if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP, &key->qP, &key->p, &key->q, NULL)) != CRYPT_OK) {
77 goto errkey;
78 }
79
80 if ((err = mp_set_int( key->e, e)) != CRYPT_OK) { goto errkey; } /* key->e = e */
81 if ((err = mp_invmod( key->e, tmp1, key->d)) != CRYPT_OK) { goto errkey; } /* key->d = 1/e mod lcm(p-1,q-1) */
82 if ((err = mp_mul( p, q, key->N)) != CRYPT_OK) { goto errkey; } /* key->N = pq */
83
84 /* optimize for CRT now */
85 /* find d mod q-1 and d mod p-1 */
86 if ((err = mp_sub_d( p, 1, tmp1)) != CRYPT_OK) { goto errkey; } /* tmp1 = q-1 */
87 if ((err = mp_sub_d( q, 1, tmp2)) != CRYPT_OK) { goto errkey; } /* tmp2 = p-1 */
88 if ((err = mp_mod( key->d, tmp1, key->dP)) != CRYPT_OK) { goto errkey; } /* dP = d mod p-1 */
89 if ((err = mp_mod( key->d, tmp2, key->dQ)) != CRYPT_OK) { goto errkey; } /* dQ = d mod q-1 */
90 if ((err = mp_invmod( q, p, key->qP)) != CRYPT_OK) { goto errkey; } /* qP = 1/q mod p */
91
92 if ((err = mp_copy( p, key->p)) != CRYPT_OK) { goto errkey; }
93 if ((err = mp_copy( q, key->q)) != CRYPT_OK) { goto errkey; }
94
95 /* set key type (in this case it's CRT optimized) */
96 key->type = PK_PRIVATE;
97
98 /* return ok and free temps */
99 err = CRYPT_OK;
100 goto cleanup;
101 errkey:
102 mp_clear_multi(key->d, key->e, key->N, key->dQ, key->dP, key->qP, key->p, key->q, NULL);
103 cleanup:
104 mp_clear_multi(tmp3, tmp2, tmp1, p, q, NULL);
105 return err;
106 }
107
108 #endif
109
110 /* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_make_key.c,v $ */
111 /* $Revision: 1.14 $ */
112 /* $Date: 2006/12/04 22:23:27 $ */