security-and-privacy/gnupg
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a couple of changes; but some parts are now broken

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This commit is contained in:
Werner Koch 1998-02-11 03:25:44 +00:00
parent d6fa02add6
commit 4c0c155922
46 changed files with 1879 additions and 433 deletions
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28
cipher/elgamal.c
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@ -311,25 +311,37 @@ elg_verify(MPI a, MPI b, MPI input, ELG_public_key *pkey )
int rc;
MPI t1;
MPI t2;
MPI base[4];
MPI exp[4];
if( !(mpi_cmp_ui( a, 0 ) > 0 && mpi_cmp( a, pkey->p ) < 0) )
return 0; /* assertion 0 < a < p failed */
t1 = mpi_alloc( mpi_get_nlimbs(a) );
t2 = mpi_alloc( mpi_get_nlimbs(a) );
/* t1 = (y^a mod p) * (a^b mod p) mod p
* fixme: should be calculated by a call which evalutes
* t1 = y^a * a^b mod p
* direct.
*/
mpi_powm( t1, pkey->y, a, pkey->p );
mpi_powm( t2, a, b, pkey->p );
mpi_mulm( t1, t1, t2, pkey->p );
#if 0
/* t1 = (y^a mod p) * (a^b mod p) mod p */
base[0] = pkey->y; exp[0] = a;
base[1] = a; exp[1] = b;
base[2] = NULL; exp[2] = NULL;
mpi_mulpowm( t1, base, exp, pkey->p );
/* t2 = g ^ input mod p */
mpi_powm( t2, pkey->g, input, pkey->p );
rc = !mpi_cmp( t1, t2 );
#else
/* t1 = g ^ - input * y ^ a * a ^ b mod p */
mpi_invm(t2, pkey->g, pkey->p );
base[0] = t2 ; exp[0] = input;
base[1] = pkey->y; exp[1] = a;
base[2] = a; exp[2] = b;
base[3] = NULL; exp[3] = NULL;
mpi_mulpowm( t1, base, exp, pkey->p );
rc = !mpi_cmp_ui( t1, 1 );
#endif
mpi_free(t1);
mpi_free(t2);