1 /*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 *
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
11 *
12 *
13 * Copyright (c) 1999 Niels Provos. All rights reserved.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 *
35 *
36 * Description of the RSA algorithm can be found e.g. from the following
37 * sources:
38 *
39 * Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1994.
40 *
41 * Jennifer Seberry and Josed Pieprzyk: Cryptography: An Introduction to
42 * Computer Security. Prentice-Hall, 1989.
43 *
44 * Man Young Rhee: Cryptography and Secure Data Communications. McGraw-Hill,
45 * 1994.
46 *
47 * R. Rivest, A. Shamir, and L. M. Adleman: Cryptographic Communications
48 * System and Method. US Patent 4,405,829, 1983.
49 *
50 * Hans Riesel: Prime Numbers and Computer Methods for Factorization.
51 * Birkhauser, 1994.
52 *
53 * The RSA Frequently Asked Questions document by RSA Data Security,
54 * Inc., 1995.
55 *
56 * RSA in 3 lines of perl by Adam Back <aba@atlax.ex.ac.uk>, 1995, as
57 * included below:
58 *
59 * [gone - had to be deleted - what a pity]
60 */
61
62 #include "includes.h"
63 RCSID("$OpenBSD: rsa.c,v 1.24 2001/12/27 18:22:16 markus Exp $");
64
65 #pragma ident "%Z%%M% %I% %E% SMI"
66
67 #include "rsa.h"
68 #include "log.h"
69 #include "xmalloc.h"
70
71 void
rsa_public_encrypt(BIGNUM * out,BIGNUM * in,RSA * key)72 rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
73 {
74 u_char *inbuf, *outbuf;
75 int len, ilen, olen;
76
77 if (BN_num_bits(key->e) < 2 || !BN_is_odd(key->e))
78 fatal("rsa_public_encrypt() exponent too small or not odd");
79
80 olen = BN_num_bytes(key->n);
81 outbuf = xmalloc(olen);
82
83 ilen = BN_num_bytes(in);
84 inbuf = xmalloc(ilen);
85 BN_bn2bin(in, inbuf);
86
87 if ((len = RSA_public_encrypt(ilen, inbuf, outbuf, key,
88 RSA_PKCS1_PADDING)) <= 0)
89 fatal("rsa_public_encrypt() failed");
90
91 BN_bin2bn(outbuf, len, out);
92
93 memset(outbuf, 0, olen);
94 memset(inbuf, 0, ilen);
95 xfree(outbuf);
96 xfree(inbuf);
97 }
98
99 int
rsa_private_decrypt(BIGNUM * out,BIGNUM * in,RSA * key)100 rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
101 {
102 u_char *inbuf, *outbuf;
103 int len, ilen, olen;
104
105 olen = BN_num_bytes(key->n);
106 outbuf = xmalloc(olen);
107
108 ilen = BN_num_bytes(in);
109 inbuf = xmalloc(ilen);
110 BN_bn2bin(in, inbuf);
111
112 if ((len = RSA_private_decrypt(ilen, inbuf, outbuf, key,
113 RSA_PKCS1_PADDING)) <= 0) {
114 error("rsa_private_decrypt() failed");
115 } else {
116 BN_bin2bn(outbuf, len, out);
117 }
118 memset(outbuf, 0, olen);
119 memset(inbuf, 0, ilen);
120 xfree(outbuf);
121 xfree(inbuf);
122 return len;
123 }
124
125 /* calculate p-1 and q-1 */
126 void
rsa_generate_additional_parameters(RSA * rsa)127 rsa_generate_additional_parameters(RSA *rsa)
128 {
129 BIGNUM *aux;
130 BN_CTX *ctx;
131
132 if ((aux = BN_new()) == NULL)
133 fatal("rsa_generate_additional_parameters: BN_new failed");
134 if ((ctx = BN_CTX_new()) == NULL)
135 fatal("rsa_generate_additional_parameters: BN_CTX_new failed");
136
137 BN_sub(aux, rsa->q, BN_value_one());
138 BN_mod(rsa->dmq1, rsa->d, aux, ctx);
139
140 BN_sub(aux, rsa->p, BN_value_one());
141 BN_mod(rsa->dmp1, rsa->d, aux, ctx);
142
143 BN_clear_free(aux);
144 BN_CTX_free(ctx);
145 }
146
147