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/*
*
* rsa.c
*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* Created: Fri Mar 3 22:07:06 1995 ylo
*
* 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"
RCSID("$Id: rsa.c,v 1.12 2000/04/03 04:50:46 damien Exp $");
#include "rsa.h"
#include "ssh.h"
#include "xmalloc.h"
#include "entropy.h"
int rsa_verbose = 1;
int
rsa_alive()
{
RSA *key;
seed_rng();
key = RSA_generate_key(32, 3, NULL, NULL);
if (key == NULL)
return (0);
RSA_free(key);
return (1);
}
/*
* Key generation progress meter callback
*/
void
keygen_progress(int p, int n, void *arg)
{
const char progress_chars[] = ".o+O?";
if ((p < 0) || (p > (sizeof(progress_chars) - 2)))
p = sizeof(progress_chars) - 2;
putchar(progress_chars[p]);
fflush(stdout);
}
/*
* Generates RSA public and private keys. This initializes the data
* structures; they should be freed with rsa_clear_private_key and
* rsa_clear_public_key.
*/
void
rsa_generate_key(RSA *prv, RSA *pub, unsigned int bits)
{
RSA *key;
seed_rng();
if (rsa_verbose) {
printf("Generating RSA keys: ");
fflush(stdout);
key = RSA_generate_key(bits, 35, keygen_progress, NULL);
printf("\n");
} else {
key = RSA_generate_key(bits, 35, NULL, NULL);
}
if (key == NULL)
fatal("rsa_generate_key: key generation failed.");
seed_rng();
/* Copy public key parameters */
pub->n = BN_new();
BN_copy(pub->n, key->n);
pub->e = BN_new();
BN_copy(pub->e, key->e);
/* Copy private key parameters */
prv->n = BN_new();
BN_copy(prv->n, key->n);
prv->e = BN_new();
BN_copy(prv->e, key->e);
prv->d = BN_new();
BN_copy(prv->d, key->d);
prv->p = BN_new();
BN_copy(prv->p, key->p);
prv->q = BN_new();
BN_copy(prv->q, key->q);
prv->dmp1 = BN_new();
BN_copy(prv->dmp1, key->dmp1);
prv->dmq1 = BN_new();
BN_copy(prv->dmq1, key->dmq1);
prv->iqmp = BN_new();
BN_copy(prv->iqmp, key->iqmp);
RSA_free(key);
if (rsa_verbose)
printf("Key generation complete.\n");
}
void
rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
unsigned 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);
}
void
rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
{
unsigned 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)
fatal("rsa_private_decrypt() failed");
BN_bin2bn(outbuf, len, out);
memset(outbuf, 0, olen);
memset(inbuf, 0, ilen);
xfree(outbuf);
xfree(inbuf);
}
/* Set whether to output verbose messages during key generation. */
void
rsa_set_verbose(int verbose)
{
rsa_verbose = verbose;
}
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