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* pubkey.c (setup_pubkey_table), elgamal.c (sign, verify, test_keys,
elg_sign, elg_verify, elg_get_info): Remove the last bits of Elgamal type 20 support.
This commit is contained in:
David Shaw
parent
2f3c2f4870
commit
65f759ae68
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@ -1,3 +1,9 @@
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2004-01-16 David Shaw <dshaw@jabberwocky.com>
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* pubkey.c (setup_pubkey_table), elgamal.c (sign, verify,
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test_keys, elg_sign, elg_verify, elg_get_info): Remove the last
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bits of Elgamal type 20 support.
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2003-12-29 David Shaw <dshaw@jabberwocky.com>
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* idea-stub.c (load_module, idea_get_info): Return the proper type
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@ -1166,7 +1172,8 @@ Mon Feb 16 10:08:47 1998 Werner Koch (wk@isil.d.shuttle.de)
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Copyright 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
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Copyright 1998, 1999, 2000, 2001, 2002, 2003,
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2004 Free Software Foundation, Inc.
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This file is free software; as a special exception the author gives
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unlimited permission to copy and/or distribute it, with or without
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@ -1175,5 +1182,3 @@ Mon Feb 16 10:08:47 1998 Werner Koch (wk@isil.d.shuttle.de)
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This file is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
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implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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164
cipher/elgamal.c
164
cipher/elgamal.c
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@ -1,5 +1,6 @@
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/* elgamal.c - elgamal Public Key encryption
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* Copyright (C) 1998, 2000, 2001, 2003 Free Software Foundation, Inc.
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* Copyright (C) 1998, 2000, 2001, 2003,
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* 2004 Free Software Foundation, Inc.
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*
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* For a description of the algorithm, see:
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* Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1996.
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@ -52,8 +53,6 @@ static void generate( ELG_secret_key *sk, unsigned nbits, MPI **factors );
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static int check_secret_key( ELG_secret_key *sk );
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static void do_encrypt(MPI a, MPI b, MPI input, ELG_public_key *pkey );
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static void decrypt(MPI output, MPI a, MPI b, ELG_secret_key *skey );
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static void sign(MPI a, MPI b, MPI input, ELG_secret_key *skey);
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static int verify(MPI a, MPI b, MPI input, ELG_public_key *pkey);
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static void (*progress_cb) ( void *, int );
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@ -141,10 +140,6 @@ test_keys( ELG_secret_key *sk, unsigned nbits )
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if( mpi_cmp( test, out2 ) )
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log_fatal("Elgamal operation: encrypt, decrypt failed\n");
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sign( out1_a, out1_b, test, sk );
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if( !verify( out1_a, out1_b, test, &pk ) )
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log_fatal("Elgamal operation: sign, verify failed\n");
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mpi_free( test );
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mpi_free( out1_a );
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mpi_free( out1_b );
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@ -375,8 +370,6 @@ do_encrypt(MPI a, MPI b, MPI input, ELG_public_key *pkey )
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}
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static void
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decrypt(MPI output, MPI a, MPI b, ELG_secret_key *skey )
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{
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@ -399,111 +392,6 @@ decrypt(MPI output, MPI a, MPI b, ELG_secret_key *skey )
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}
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/****************
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* Make an Elgamal signature out of INPUT
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*/
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static void
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sign(MPI a, MPI b, MPI input, ELG_secret_key *skey )
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{
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MPI k;
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MPI t = mpi_alloc( mpi_get_nlimbs(a) );
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MPI inv = mpi_alloc( mpi_get_nlimbs(a) );
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MPI p_1 = mpi_copy(skey->p);
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/*
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* b = (t * inv) mod (p-1)
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* b = (t * inv(k,(p-1),(p-1)) mod (p-1)
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* b = (((M-x*a) mod (p-1)) * inv(k,(p-1),(p-1))) mod (p-1)
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*
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*/
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mpi_sub_ui(p_1, p_1, 1);
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k = gen_k( skey->p, 0 /* no small K ! */ );
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mpi_powm( a, skey->g, k, skey->p );
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mpi_mul(t, skey->x, a );
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mpi_subm(t, input, t, p_1 );
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while( mpi_is_neg(t) ) {
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BUG(); /* That is nonsense code - left over from a very early test?*/
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mpi_add(t, t, p_1);
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}
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mpi_invm(inv, k, p_1 );
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mpi_mulm(b, t, inv, p_1 );
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#if 0
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if( DBG_CIPHER ) {
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log_mpidump("elg sign p= ", skey->p);
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log_mpidump("elg sign g= ", skey->g);
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log_mpidump("elg sign y= ", skey->y);
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log_mpidump("elg sign x= ", skey->x);
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log_mpidump("elg sign k= ", k);
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log_mpidump("elg sign M= ", input);
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log_mpidump("elg sign a= ", a);
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log_mpidump("elg sign b= ", b);
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}
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#endif
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mpi_free(k);
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mpi_free(t);
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mpi_free(inv);
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mpi_free(p_1);
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}
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/****************
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* Returns true if the signature composed of A and B is valid.
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*/
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static int
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verify(MPI a, MPI b, MPI input, ELG_public_key *pkey )
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{
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int rc;
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MPI t1;
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MPI t2;
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MPI base[4];
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MPI exp[4];
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if( !(mpi_cmp_ui( a, 0 ) > 0 && mpi_cmp( a, pkey->p ) < 0) )
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return 0; /* assertion 0 < a < p failed */
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t1 = mpi_alloc( mpi_get_nlimbs(a) );
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t2 = mpi_alloc( mpi_get_nlimbs(a) );
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#if 0
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/* t1 = (y^a mod p) * (a^b mod p) mod p */
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mpi_powm( t1, pkey->y, a, pkey->p );
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mpi_powm( t2, a, b, pkey->p );
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mpi_mulm( t1, t1, t2, pkey->p );
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/* t2 = g ^ input mod p */
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mpi_powm( t2, pkey->g, input, pkey->p );
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rc = !mpi_cmp( t1, t2 );
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#elif 0
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/* t1 = (y^a mod p) * (a^b mod p) mod p */
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base[0] = pkey->y; exp[0] = a;
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base[1] = a; exp[1] = b;
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base[2] = NULL; exp[2] = NULL;
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mpi_mulpowm( t1, base, exp, pkey->p );
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/* t2 = g ^ input mod p */
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mpi_powm( t2, pkey->g, input, pkey->p );
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rc = !mpi_cmp( t1, t2 );
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#else
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/* t1 = g ^ - input * y ^ a * a ^ b mod p */
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mpi_invm(t2, pkey->g, pkey->p );
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base[0] = t2 ; exp[0] = input;
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base[1] = pkey->y; exp[1] = a;
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base[2] = a; exp[2] = b;
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base[3] = NULL; exp[3] = NULL;
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mpi_mulpowm( t1, base, exp, pkey->p );
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rc = !mpi_cmp_ui( t1, 1 );
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#endif
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mpi_free(t1);
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mpi_free(t2);
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return rc;
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}
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/*********************************************
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************** interface ******************
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*********************************************/
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@ -546,7 +434,6 @@ elg_check_secret_key( int algo, MPI *skey )
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}
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int
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elg_encrypt( int algo, MPI *resarr, MPI data, MPI *pkey )
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{
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@ -586,45 +473,6 @@ elg_decrypt( int algo, MPI *result, MPI *data, MPI *skey )
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return 0;
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}
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int
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elg_sign( int algo, MPI *resarr, MPI data, MPI *skey )
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{
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ELG_secret_key sk;
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if( !is_ELGAMAL(algo) )
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return G10ERR_PUBKEY_ALGO;
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if( !data || !skey[0] || !skey[1] || !skey[2] || !skey[3] )
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return G10ERR_BAD_MPI;
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sk.p = skey[0];
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sk.g = skey[1];
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sk.y = skey[2];
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sk.x = skey[3];
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resarr[0] = mpi_alloc( mpi_get_nlimbs( sk.p ) );
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resarr[1] = mpi_alloc( mpi_get_nlimbs( sk.p ) );
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sign( resarr[0], resarr[1], data, &sk );
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return 0;
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}
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int
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elg_verify( int algo, MPI hash, MPI *data, MPI *pkey )
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{
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ELG_public_key pk;
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if( !is_ELGAMAL(algo) )
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return G10ERR_PUBKEY_ALGO;
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if( !data[0] || !data[1] || !hash
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|| !pkey[0] || !pkey[1] || !pkey[2] )
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return G10ERR_BAD_MPI;
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pk.p = pkey[0];
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pk.g = pkey[1];
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pk.y = pkey[2];
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if( !verify( data[0], data[1], hash, &pk ) )
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return G10ERR_BAD_SIGN;
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return 0;
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}
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unsigned int
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elg_get_nbits( int algo, MPI *pkey )
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@ -642,9 +490,6 @@ elg_get_nbits( int algo, MPI *pkey )
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* the ALGO is invalid.
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* Usage: Bit 0 set : allows signing
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* 1 set : allows encryption
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* NOTE: This function allows signing also for ELG-E, which is not
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* okay but a bad hack to allow to work with old gpg keys. The real check
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* is done in the gnupg ocde depending on the packet version.
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*/
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const char *
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elg_get_info( int algo, int *npkey, int *nskey, int *nenc, int *nsig,
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@ -656,11 +501,8 @@ elg_get_info( int algo, int *npkey, int *nskey, int *nenc, int *nsig,
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*nsig = 2;
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switch( algo ) {
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case PUBKEY_ALGO_ELGAMAL:
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*use = PUBKEY_USAGE_SIG|PUBKEY_USAGE_ENC;
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return "ELG";
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case PUBKEY_ALGO_ELGAMAL_E:
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*use = PUBKEY_USAGE_SIG|PUBKEY_USAGE_ENC;
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*use = PUBKEY_USAGE_ENC;
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return "ELG-E";
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default: *use = 0; return NULL;
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}
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@ -1,5 +1,6 @@
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/* pubkey.c - pubkey dispatcher
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* Copyright (C) 1998, 1999, 2000, 2001, 2003 Free Software Foundation, Inc.
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* Copyright (C) 1998, 1999, 2000, 2001, 2003,
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* 2004 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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@ -97,23 +98,6 @@ setup_pubkey_table(void)
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{
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int i=0;
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pubkey_table[i].algo = PUBKEY_ALGO_ELGAMAL;
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pubkey_table[i].name = elg_get_info( pubkey_table[i].algo,
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&pubkey_table[i].npkey,
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&pubkey_table[i].nskey,
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&pubkey_table[i].nenc,
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&pubkey_table[i].nsig,
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&pubkey_table[i].use );
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pubkey_table[i].generate = elg_generate;
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pubkey_table[i].check_secret_key = elg_check_secret_key;
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pubkey_table[i].encrypt = elg_encrypt;
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pubkey_table[i].decrypt = elg_decrypt;
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pubkey_table[i].sign = elg_sign;
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pubkey_table[i].verify = elg_verify;
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pubkey_table[i].get_nbits = elg_get_nbits;
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if( !pubkey_table[i].name )
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BUG();
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i++;
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pubkey_table[i].algo = PUBKEY_ALGO_ELGAMAL_E;
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pubkey_table[i].name = elg_get_info( pubkey_table[i].algo,
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&pubkey_table[i].npkey,
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