/* $OpenBSD: rsa.c,v 1.28 2006/08/03 03:34:42 deraadt 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 <sys/types.h> #include <stdarg.h> #include <string.h> #include "xmalloc.h" #include "rsa.h" #include "log.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); }