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Diffstat (limited to 'cipher/rsa.c')
| -rw-r--r-- | cipher/rsa.c | 214 |
1 files changed, 0 insertions, 214 deletions
diff --git a/cipher/rsa.c b/cipher/rsa.c deleted file mode 100644 index db82b48d7..000000000 --- a/cipher/rsa.c +++ /dev/null @@ -1,214 +0,0 @@ -/* rsa.c - RSA function - * Copyright (c) 1997 by Werner Koch (dd9jn) - * - * ATTENTION: This code should not be exported from the United States - * nor should it be used their without a license agreement with PKP. - * The RSA alorithm is protected by U.S. Patent #4,405,829 which - * expires on September 20, 2000! - * - * For a description of the algorithm, see: - * Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1996. - * ISBN 0-471-11709-9. Pages 466 ff. - * - * This file is part of G10. - * - * G10 is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * G10 is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA - */ - -#include <config.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include "util.h" -#include "mpi.h" -#include "cipher.h" - - -void -rsa_free_public_key( RSA_public_key *pk ) -{ - mpi_free( pk->n ); pk->n = NULL; - mpi_free( pk->e ); pk->e = NULL; -} - -void -rsa_free_secret_key( RSA_secret_key *sk ) -{ - mpi_free( sk->e ); sk->e = NULL; - mpi_free( sk->n ); sk->n = NULL; - mpi_free( sk->p ); sk->p = NULL; - mpi_free( sk->q ); sk->q = NULL; - mpi_free( sk->d ); sk->d = NULL; - mpi_free( sk->u ); sk->u = NULL; -} - - -static void -test_keys( RSA_public_key *pk, RSA_secret_key *sk, unsigned nbits ) -{ - MPI test = mpi_alloc( nbits / BITS_PER_MPI_LIMB ); - MPI out1 = mpi_alloc( nbits / BITS_PER_MPI_LIMB ); - MPI out2 = mpi_alloc( nbits / BITS_PER_MPI_LIMB ); - - mpi_set_bytes( test, nbits, get_random_byte, 0 ); - - rsa_public( out1, test, pk ); - rsa_secret( out2, out1, sk ); - if( mpi_cmp( test, out2 ) ) - log_fatal("RSA operation: public, secret failed\n"); - rsa_secret( out1, test, sk ); - rsa_public( out2, out1, pk ); - if( mpi_cmp( test, out2 ) ) - log_fatal("RSA operation: secret, public failed\n"); - mpi_free( test ); - mpi_free( out1 ); - mpi_free( out2 ); -} - -/**************** - * Generate a key pair with a key of size NBITS - * Returns: 2 structures filles with all needed values - */ -void -rsa_generate( RSA_public_key *pk, RSA_secret_key *sk, unsigned nbits ) -{ - MPI p, q; /* the two primes */ - MPI d; /* the private key */ - MPI u; - MPI t1, t2; - MPI n; /* the public key */ - MPI e; /* the exponent */ - MPI phi; /* helper: (p-a)(q-1) */ - MPI g; - MPI f; - - /* select two (very secret) primes */ - p = generate_secret_prime( nbits / 2 ); - q = generate_secret_prime( nbits / 2 ); - if( mpi_cmp( p, q ) > 0 ) /* p shall be smaller than q (for calc of u)*/ - mpi_swap(p,q); - /* calculate Euler totient: phi = (p-1)(q-1) */ - t1 = mpi_alloc_secure( mpi_get_nlimbs(p) ); - t2 = mpi_alloc_secure( mpi_get_nlimbs(p) ); - phi = mpi_alloc_secure( nbits / BITS_PER_MPI_LIMB ); - g = mpi_alloc_secure( nbits / BITS_PER_MPI_LIMB ); - f = mpi_alloc_secure( nbits / BITS_PER_MPI_LIMB ); - mpi_sub_ui( t1, p, 1 ); - mpi_sub_ui( t2, q, 1 ); - mpi_mul( phi, t1, t2 ); - mpi_gcd(g, t1, t2); - mpi_fdiv_q(f, phi, g); - /* multiply them to make the private key */ - n = mpi_alloc( nbits / BITS_PER_MPI_LIMB ); - mpi_mul( n, p, q ); - /* find a public exponent */ - e = mpi_alloc(1); - mpi_set_ui( e, 17); /* start with 17 */ - while( !mpi_gcd(t1, e, phi) ) /* (while gcd is not 1) */ - mpi_add_ui( e, e, 2); - /* calculate the secret key d = e^1 mod phi */ - d = mpi_alloc( nbits / BITS_PER_MPI_LIMB ); - mpi_invm(d, e, f ); - /* calculate the inverse of p and q (used for chinese remainder theorem)*/ - u = mpi_alloc( nbits / BITS_PER_MPI_LIMB ); - mpi_invm(u, p, q ); - - if( DBG_CIPHER ) { - log_mpidump(" p= ", p ); - log_mpidump(" q= ", q ); - log_mpidump("phi= ", phi ); - log_mpidump(" g= ", g ); - log_mpidump(" f= ", f ); - log_mpidump(" n= ", n ); - log_mpidump(" e= ", e ); - log_mpidump(" d= ", d ); - log_mpidump(" u= ", u ); - } - - mpi_free(t1); - mpi_free(t2); - mpi_free(phi); - mpi_free(f); - mpi_free(g); - - pk->n = mpi_copy(n); - pk->e = mpi_copy(e); - sk->n = n; - sk->e = e; - sk->p = p; - sk->q = q; - sk->d = d; - sk->u = u; - - /* now we can test our keys (this should never fail!) */ - test_keys( pk, sk, nbits - 64 ); -} - - -/**************** - * Test wether the secret key is valid. - * Returns: true if this is a valid key. - */ -int -rsa_check_secret_key( RSA_secret_key *sk ) -{ - int rc; - MPI temp = mpi_alloc( mpi_get_nlimbs(sk->p)*2 ); - - mpi_mul(temp, sk->p, sk->q ); - rc = mpi_cmp( temp, sk->n ); - mpi_free(temp); - return !rc; -} - - - -/**************** - * Public key operation. Encrypt INPUT with PKEY and put result into OUTPUT. - * - * c = m^e mod n - * - * Where c is OUTPUT, m is INPUT and e,n are elements of PKEY. - */ -void -rsa_public(MPI output, MPI input, RSA_public_key *pkey ) -{ - if( output == input ) { /* powm doesn't like output and input the same */ - MPI x = mpi_alloc( mpi_get_nlimbs(input)*2 ); - mpi_powm( x, input, pkey->e, pkey->n ); - mpi_set(output, x); - mpi_free(x); - } - else - mpi_powm( output, input, pkey->e, pkey->n ); -} - -/**************** - * Secret key operation. Encrypt INPUT with SKEY and put result into OUTPUT. - * - * m = c^d mod n - * - * Where m is OUTPUT, c is INPUT and d,n are elements of PKEY. - * - * FIXME: We should better use the Chinese Remainder Theorem - */ -void -rsa_secret(MPI output, MPI input, RSA_secret_key *skey ) -{ - mpi_powm( output, input, skey->d, skey->n ); -} - - - |