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/* $OpenBSD: rsa.c,v 1.27 2006/07/22 20:48:23 stevesk Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
*
* Copyright (c) 1999 Niels Provos. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* Description of the RSA algorithm can be found e.g. from the following
* sources:
*
* Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1994.
*
* Jennifer Seberry and Josed Pieprzyk: Cryptography: An Introduction to
* Computer Security. Prentice-Hall, 1989.
*
* Man Young Rhee: Cryptography and Secure Data Communications. McGraw-Hill,
* 1994.
*
* R. Rivest, A. Shamir, and L. M. Adleman: Cryptographic Communications
* System and Method. US Patent 4,405,829, 1983.
*
* Hans Riesel: Prime Numbers and Computer Methods for Factorization.
* Birkhauser, 1994.
*
* The RSA Frequently Asked Questions document by RSA Data Security,
* Inc., 1995.
*
* RSA in 3 lines of perl by Adam Back <aba@atlax.ex.ac.uk>, 1995, as
* included below:
*
* [gone - had to be deleted - what a pity]
*/
#include "includes.h"
#include <string.h>
#include "rsa.h"
#include "log.h"
#include "xmalloc.h"
void
rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
u_char *inbuf, *outbuf;
int len, ilen, olen;
if (BN_num_bits(key->e) < 2 || !BN_is_odd(key->e))
fatal("rsa_public_encrypt() exponent too small or not odd");
olen = BN_num_bytes(key->n);
outbuf = xmalloc(olen);
ilen = BN_num_bytes(in);
inbuf = xmalloc(ilen);
BN_bn2bin(in, inbuf);
if ((len = RSA_public_encrypt(ilen, inbuf, outbuf, key,
RSA_PKCS1_PADDING)) <= 0)
fatal("rsa_public_encrypt() failed");
BN_bin2bn(outbuf, len, out);
memset(outbuf, 0, olen);
memset(inbuf, 0, ilen);
xfree(outbuf);
xfree(inbuf);
}
int
rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
u_char *inbuf, *outbuf;
int len, ilen, olen;
olen = BN_num_bytes(key->n);
outbuf = xmalloc(olen);
ilen = BN_num_bytes(in);
inbuf = xmalloc(ilen);
BN_bn2bin(in, inbuf);
if ((len = RSA_private_decrypt(ilen, inbuf, outbuf, key,
RSA_PKCS1_PADDING)) <= 0) {
error("rsa_private_decrypt() failed");
} else {
BN_bin2bn(outbuf, len, out);
}
memset(outbuf, 0, olen);
memset(inbuf, 0, ilen);
xfree(outbuf);
xfree(inbuf);
return len;
}
/* calculate p-1 and q-1 */
void
rsa_generate_additional_parameters(RSA *rsa)
{
BIGNUM *aux;
BN_CTX *ctx;
if ((aux = BN_new()) == NULL)
fatal("rsa_generate_additional_parameters: BN_new failed");
if ((ctx = BN_CTX_new()) == NULL)
fatal("rsa_generate_additional_parameters: BN_CTX_new failed");
BN_sub(aux, rsa->q, BN_value_one());
BN_mod(rsa->dmq1, rsa->d, aux, ctx);
BN_sub(aux, rsa->p, BN_value_one());
BN_mod(rsa->dmp1, rsa->d, aux, ctx);
BN_clear_free(aux);
BN_CTX_free(ctx);
}
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