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| author | Werner Koch <[email protected]> | 1997-12-19 11:41:47 +0000 |
|---|---|---|
| committer | Werner Koch <[email protected]> | 1997-12-19 11:41:47 +0000 |
| commit | ee8d92fefa5902f97e92856b9c657fb18d0dd93e (patch) | |
| tree | cf86cf2d45d7dbeb3f8c01a53402435ac1257f88 /cipher/elgamal.c | |
| parent | added some stuff for signing keys (diff) | |
| download | gnupg-ee8d92fefa5902f97e92856b9c657fb18d0dd93e.tar.gz gnupg-ee8d92fefa5902f97e92856b9c657fb18d0dd93e.zip | |
better prime number generator. improved ELG key generation
Diffstat (limited to 'cipher/elgamal.c')
| -rw-r--r-- | cipher/elgamal.c | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/cipher/elgamal.c b/cipher/elgamal.c index 4252b48d1..3cc632525 100644 --- a/cipher/elgamal.c +++ b/cipher/elgamal.c @@ -94,7 +94,7 @@ gen_k( MPI p ) for(;;) { if( DBG_CIPHER ) fputc('.', stderr); - mpi_set_bytes( k, nbits, get_random_byte, 1 ); + mpi_set_bytes( k, nbits , get_random_byte, 1 ); if( !(mpi_cmp( k, p_1 ) < 0) ) /* check: k < (p-1) */ continue; /* no */ if( !(mpi_cmp_ui( k, 0 ) > 0) ) /* check: k > 0 */ @@ -123,19 +123,23 @@ elg_generate( ELG_public_key *pk, ELG_secret_key *sk, unsigned nbits ) MPI x; /* the secret exponent */ MPI y; MPI temp; + unsigned qbits; - p = NULL; p_min1 = mpi_alloc( (nbits+BITS_PER_MPI_LIMB-1)/BITS_PER_MPI_LIMB ); temp = mpi_alloc( (nbits+BITS_PER_MPI_LIMB-1)/BITS_PER_MPI_LIMB ); - /*do {*/ - mpi_free(p); - /* FIXME!!!! Should generate a strong prime */ - p = generate_public_prime( nbits ); - mpi_sub_ui(p_min1, p, 1); - /*} while if( mpi_gcd( temp, k, p_1 ) )*/ + if( nbits < 512 ) + qbits = 120; + else if( nbits <= 1024 ) + qbits = 160; + else if( nbits <= 2048 ) + qbits = 200; + else + qbits = 240; + g = mpi_alloc(1); + p = generate_elg_prime( nbits, qbits, g ); + mpi_sub_ui(p_min1, p, 1); - g = mpi_alloc_set_ui(3); /* fixme: 3 is bad (but better than 2)*/ /* select a random number which has these properties: * 0 < x < p-1 */ |