diff options
author | Matt Johnston <matt@ucc.asn.au> | 2004-06-01 02:46:09 +0000 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2004-06-01 02:46:09 +0000 |
commit | 674a60748884dc55ee7091b7c23a41240e75f73c (patch) | |
tree | 3b5a173c356f867b94df3873b57ff36d33129ea7 /genrsa.c |
Makefile.in contains updated files required
--HG--
extra : convert_revision : cc8a8c49dc70e632c352853a39801089b08149be
Diffstat (limited to 'genrsa.c')
-rw-r--r-- | genrsa.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/genrsa.c b/genrsa.c new file mode 100644 index 0000000..330ebf2 --- /dev/null +++ b/genrsa.c @@ -0,0 +1,138 @@ +/* + * 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; + mp_int pminus, qminus, 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; + 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 */ + + if (mp_read_unsigned_bin(prime, buf, size+1) != MP_OKAY) { + fprintf(stderr, "rsa generation failed\n"); + exit(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 */ |