Mercurial > dropbear
view genrsa.c @ 329:8ed0dce45126
disapproval of revision 'a4c1a9be4db326f8f7adcf30f876fadedf87b203'
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sat, 10 Jun 2006 16:39:37 +0000 |
parents | c9483550701b |
children | 740e782679be 657c045054ab |
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/* * Dropbear - a SSH2 server * * Copyright (c) 2002,2003 Matt Johnston * All rights reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #include "includes.h" #include "dbutil.h" #include "bignum.h" #include "random.h" #include "rsa.h" #include "genrsa.h" #define RSA_E 65537 #ifdef DROPBEAR_RSA static void getrsaprime(mp_int* prime, mp_int *primeminus, mp_int* rsa_e, unsigned int size); /* mostly taken from libtomcrypt's rsa key generation routine */ rsa_key * gen_rsa_priv_key(unsigned int size) { rsa_key * key; DEF_MP_INT(pminus); DEF_MP_INT(qminus); DEF_MP_INT(lcm); key = (rsa_key*)m_malloc(sizeof(rsa_key)); key->e = (mp_int*)m_malloc(sizeof(mp_int)); key->n = (mp_int*)m_malloc(sizeof(mp_int)); key->d = (mp_int*)m_malloc(sizeof(mp_int)); key->p = (mp_int*)m_malloc(sizeof(mp_int)); key->q = (mp_int*)m_malloc(sizeof(mp_int)); m_mp_init_multi(key->e, key->n, key->d, key->p, key->q, &pminus, &lcm, &qminus, NULL); seedrandom(); if (mp_set_int(key->e, RSA_E) != MP_OKAY) { fprintf(stderr, "rsa generation failed\n"); exit(1); } /* PuTTY doesn't like it if the modulus isn't a multiple of 8 bits, * so we just generate them until we get one which is OK */ getrsaprime(key->p, &pminus, key->e, size/2); do { getrsaprime(key->q, &qminus, key->e, size/2); if (mp_mul(key->p, key->q, key->n) != MP_OKAY) { fprintf(stderr, "rsa generation failed\n"); exit(1); } } while (mp_count_bits(key->n) % 8 != 0); /* lcm(p-1, q-1) */ if (mp_lcm(&pminus, &qminus, &lcm) != MP_OKAY) { fprintf(stderr, "rsa generation failed\n"); exit(1); } /* de = 1 mod lcm(p-1,q-1) */ /* therefore d = (e^-1) mod lcm(p-1,q-1) */ if (mp_invmod(key->e, &lcm, key->d) != MP_OKAY) { fprintf(stderr, "rsa generation failed\n"); exit(1); } mp_clear_multi(&pminus, &qminus, &lcm, NULL); return key; } /* return a prime suitable for p or q */ static void getrsaprime(mp_int* prime, mp_int *primeminus, mp_int* rsa_e, unsigned int size) { unsigned char *buf; DEF_MP_INT(temp_gcd); buf = (unsigned char*)m_malloc(size+1); m_mp_init(&temp_gcd); do { /* generate a random odd number with MSB set, then find the the next prime above it */ genrandom(buf, size+1); buf[0] |= 0x80; /* MSB set */ bytes_to_mp(prime, buf, size+1); /* find the next integer which is prime, 8 round of miller-rabin */ if (mp_prime_next_prime(prime, 8, 0) != MP_OKAY) { fprintf(stderr, "rsa generation failed\n"); exit(1); } /* subtract one to get p-1 */ if (mp_sub_d(prime, 1, primeminus) != MP_OKAY) { fprintf(stderr, "rsa generation failed\n"); exit(1); } /* check relative primality to e */ if (mp_gcd(primeminus, rsa_e, &temp_gcd) != MP_OKAY) { fprintf(stderr, "rsa generation failed\n"); exit(1); } } while (mp_cmp_d(&temp_gcd, 1) != MP_EQ); /* while gcd(p-1, e) != 1 */ /* now we have a good value for result */ mp_clear(&temp_gcd); m_burn(buf, size+1); m_free(buf); } #endif /* DROPBEAR_RSA */