add DSA key generation

This commit is contained in:
Werner Koch 1998-05-05 20:34:20 +00:00
parent 42b03f6ebd
commit 69cf10ffab
17 changed files with 324 additions and 29 deletions

2
THANKS
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@ -24,6 +24,8 @@ Ulf M
Walter Koch walterk@ddorf.rhein-ruhr.de
Werner Koch werner.koch@guug.de
Wim Vandeputte bunbun@reptile.rug.ac.be
tzeruch@ceddec.com
Thanks to the German Unix User Group for providing FTP space and
Martin Hamilton for hosting the mailing list.

2
TODO
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@ -47,3 +47,5 @@
* add readline support (but how can we allcoate it in secure memory?)
* add a testcase for --print-mds

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@ -1 +1 @@
0.2.17
0.2.17a

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@ -1,3 +1,13 @@
Tue May 5 21:28:55 1998 Werner Koch (wk@isil.d.shuttle.de)
* elgamal.c (elg_generate): choosing x was not correct, could
yield 6 bytes which are not from the random pool, tsss, tsss..
Tue May 5 14:09:06 1998 Werner Koch (wk@isil.d.shuttle.de)
* primegen.c (generate_elg_prime): Add arg mode, changed all
callers and implemented mode 1.
Mon Apr 27 14:41:58 1998 Werner Koch (wk@isil.d.shuttle.de)
* cipher.c (cipher_get_keylen): New.

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@ -22,6 +22,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "util.h"
#include "mpi.h"
#include "cipher.h"
@ -74,6 +75,123 @@ dsa_free_secret_key( DSA_secret_key *sk )
}
static void
test_keys( DSA_public_key *pk, DSA_secret_key *sk, unsigned qbits )
{
MPI test = mpi_alloc( qbits / BITS_PER_MPI_LIMB );
MPI out1_a = mpi_alloc( qbits / BITS_PER_MPI_LIMB );
MPI out1_b = mpi_alloc( qbits / BITS_PER_MPI_LIMB );
mpi_set_bytes( test, qbits, get_random_byte, 0 );
dsa_sign( out1_a, out1_b, test, sk );
if( !dsa_verify( out1_a, out1_b, test, pk ) )
log_fatal("DSA:: sign, verify failed\n");
mpi_free( test );
mpi_free( out1_a );
mpi_free( out1_b );
}
/****************
* Generate a DSA key pair with a key of size NBITS
* Returns: 2 structures filled with all needed values
* and an array with the n-1 factors of (p-1)
*/
void
dsa_generate( DSA_public_key *pk, DSA_secret_key *sk,
unsigned nbits, MPI **ret_factors )
{
MPI p; /* the prime */
MPI q; /* the 160 bit prime factor */
MPI g; /* the generator */
MPI y; /* g^x mod p */
MPI x; /* the secret exponent */
MPI h, e; /* helper */
unsigned qbits;
byte *rndbuf;
assert( nbits >= 512 && nbits <= 1024 );
qbits = 160;
p = generate_elg_prime( 1, nbits, qbits, NULL, ret_factors );
/* get q out of factors */
q = mpi_copy((*ret_factors)[0]);
if( mpi_get_nbits(q) != qbits )
BUG();
/* find a generator g (h and e are helpers)*/
/* e = (p-1)/q */
e = mpi_alloc( mpi_get_nlimbs(p) );
mpi_sub_ui( e, p, 1 );
mpi_fdiv_q( e, e, q );
g = mpi_alloc( mpi_get_nlimbs(p) );
h = mpi_alloc_set_ui( 1 ); /* we start with 2 */
do {
mpi_add_ui( h, h, 1 );
/* g = h^e mod p */
mpi_powm( g, h, e, p );
} while( !mpi_cmp_ui( g, 1 ) ); /* continue until g != 1 */
/* select a random number which has these properties:
* 0 < x < q-1
* This must be a very good random number because this
* is the secret part. */
if( DBG_CIPHER )
log_debug("choosing a random x ");
assert( qbits >= 16 );
x = mpi_alloc_secure( mpi_get_nlimbs(q) );
mpi_sub_ui( h, q, 1 ); /* put q-1 into h */
rndbuf = NULL;
do {
if( DBG_CIPHER )
fputc('.', stderr);
if( !rndbuf )
rndbuf = get_random_bits( qbits, 2, 1 );
else { /* change only some of the higher bits (= 2 bytes)*/
char *r = get_random_bits( 16, 2, 1 );
memcpy(rndbuf, r, 16/8 );
m_free(r);
}
mpi_set_buffer( x, rndbuf, (qbits+7)/8, 0 );
mpi_clear_highbit( x, qbits+1 );
} while( !( mpi_cmp_ui( x, 0 )>0 && mpi_cmp( x, h )<0 ) );
m_free(rndbuf);
mpi_free( e );
mpi_free( h );
/* y = g^x mod p */
y = mpi_alloc( mpi_get_nlimbs(p) );
mpi_powm( y, g, x, p );
if( DBG_CIPHER ) {
fputc('\n', stderr);
log_mpidump("dsa p= ", p );
log_mpidump("dsa q= ", q );
log_mpidump("dsa g= ", g );
log_mpidump("dsa y= ", y );
log_mpidump("dsa x= ", x );
}
/* copy the stuff to the key structures */
pk->p = mpi_copy(p);
pk->q = mpi_copy(q);
pk->g = mpi_copy(g);
pk->y = mpi_copy(y);
sk->p = p;
sk->q = q;
sk->g = g;
sk->y = y;
sk->x = x;
/* now we can test our keys (this should never fail!) */
test_keys( pk, sk, qbits );
}
/****************
* Test whether the secret key is valid.
* Returns: if this is a valid key.

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@ -41,8 +41,9 @@ typedef struct {
void dsa_free_public_key( DSA_public_key *pk );
void dsa_free_secret_key( DSA_secret_key *sk );
void dsa_generate( DSA_public_key *pk, DSA_secret_key *sk, unsigned nbits );
int dsa_check_secret_key( DSA_secret_key *sk );
void dsa_generate( DSA_public_key *pk, DSA_secret_key *sk,
unsigned nbits, MPI **ret_factors );
void dsa_sign(MPI r, MPI s, MPI input, DSA_secret_key *skey);
int dsa_verify(MPI r, MPI s, MPI input, DSA_public_key *pkey);

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@ -139,7 +139,7 @@ elg_generate( ELG_public_key *pk, ELG_secret_key *sk,
else
qbits = 240;
g = mpi_alloc(1);
p = generate_elg_prime( nbits, qbits, g, ret_factors );
p = generate_elg_prime( 0, nbits, qbits, g, ret_factors );
mpi_sub_ui(p_min1, p, 1);
@ -163,7 +163,7 @@ elg_generate( ELG_public_key *pk, ELG_secret_key *sk,
}
else {
char *r = get_random_bits( 16, 2, 1 );
memcpy(rndbuf, r, 16 );
memcpy(rndbuf, r, 16/8 );
m_free(r);
}
}

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@ -63,37 +63,49 @@ generate_public_prime( unsigned nbits )
* security from it - The prime number is public and we could also
* offer the factors for those who are willing to check that it is
* indeed a strong prime.
*
* mode 0: Standard
* 1: Make sure that at least one factor is of size qbits.
*/
MPI
generate_elg_prime( unsigned pbits, unsigned qbits, MPI g, MPI **ret_factors )
generate_elg_prime( int mode, unsigned pbits, unsigned qbits,
MPI g, MPI **ret_factors )
{
int n; /* number of factors */
int m; /* number of primes in pool */
unsigned fbits; /* length of prime factors */
MPI *factors; /* current factors */
MPI *pool; /* pool of primes */
MPI q; /* first prime factor */
MPI q; /* first prime factor (variable)*/
MPI prime; /* prime test value */
MPI q_factor; /* used for mode 1 */
byte *perms = NULL;
int i, j;
int count1, count2;
unsigned nprime;
unsigned req_qbits = qbits; /* the requested q bits size */
/* find number of needed prime factors */
for(n=1; (pbits - qbits - 1) / n >= qbits; n++ )
;
n--;
if( !n )
if( !n || (mode==1 && n < 2) )
log_fatal("can't gen prime with pbits=%u qbits=%u\n", pbits, qbits );
fbits = (pbits - qbits -1) / n;
while( qbits + n*fbits < pbits )
qbits++;
if( mode == 1 ) {
n--;
fbits = (pbits - 2*req_qbits -1) / n;
qbits = pbits - req_qbits - n*fbits;
}
else {
fbits = (pbits - req_qbits -1) / n;
qbits = pbits - n*fbits;
}
if( DBG_CIPHER )
log_debug("gen prime: pbits=%u qbits=%u fbits=%u n=%d\n",
pbits, qbits, fbits, n );
log_debug("gen prime: pbits=%u qbits=%u fbits=%u/%u n=%d\n",
pbits, req_qbits, qbits, fbits, n );
prime = mpi_alloc( (pbits + BITS_PER_MPI_LIMB - 1) / BITS_PER_MPI_LIMB );
q = gen_prime( qbits, 0, 1 );
q_factor = mode==1? gen_prime( req_qbits, 0, 1 ) : NULL;
/* allocate an array to hold the factors + 2 for later usage */
factors = m_alloc_clear( (n+2) * sizeof *factors );
@ -139,6 +151,8 @@ generate_elg_prime( unsigned pbits, unsigned qbits, MPI g, MPI **ret_factors )
mpi_set( prime, q );
mpi_mul_ui( prime, prime, 2 );
if( mode == 1 )
mpi_mul( prime, prime, q_factor );
for(i=0; i < n; i++ )
mpi_mul( prime, prime, factors[i] );
mpi_add_ui( prime, prime, 1 );
@ -171,18 +185,30 @@ generate_elg_prime( unsigned pbits, unsigned qbits, MPI g, MPI **ret_factors )
putc('\n', stderr);
log_mpidump( "prime : ", prime );
log_mpidump( "factor q: ", q );
if( mode == 1 )
log_mpidump( "factor q0: ", q_factor );
for(i=0; i < n; i++ )
log_mpidump( "factor pi: ", factors[i] );
log_debug("bit sizes: prime=%u, q=%u", mpi_get_nbits(prime), mpi_get_nbits(q) );
if( mode == 1 )
fprintf(stderr, ", q0=%u", mpi_get_nbits(q_factor) );
for(i=0; i < n; i++ )
fprintf(stderr, ", p%d=%u", i, mpi_get_nbits(factors[i]) );
putc('\n', stderr);
}
if( ret_factors ) { /* caller wants the factors */
*ret_factors = m_alloc_clear( (n+1) * sizeof **ret_factors );
for(i=0; i < n; i++ )
(*ret_factors)[i] = mpi_copy( factors[i] );
*ret_factors = m_alloc_clear( (n+2) * sizeof **ret_factors);
if( mode == 1 ) {
i = 0;
(*ret_factors)[i++] = mpi_copy( q_factor );
for(; i <= n; i++ )
(*ret_factors)[i] = mpi_copy( factors[i] );
}
else {
for(; i < n; i++ )
(*ret_factors)[i] = mpi_copy( factors[i] );
}
}
if( g ) { /* create a generator (start with 3)*/
@ -190,6 +216,8 @@ generate_elg_prime( unsigned pbits, unsigned qbits, MPI g, MPI **ret_factors )
MPI b = mpi_alloc( mpi_get_nlimbs(prime) );
MPI pmin1 = mpi_alloc( mpi_get_nlimbs(prime) );
if( mode == 1 )
BUG(); /* not yet implemented */
factors[n] = q;
factors[n+1] = mpi_alloc_set_ui(2);
mpi_sub_ui( pmin1, prime, 1 );
@ -230,6 +258,7 @@ generate_elg_prime( unsigned pbits, unsigned qbits, MPI g, MPI **ret_factors )
}
static MPI
gen_prime( unsigned nbits, int secret, int randomlevel )
{

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@ -702,10 +702,11 @@ transform( TIGER_CONTEXT *hd, byte *data )
u64 a,b,c,aa,bb,cc;
u64 x[8];
#ifdef BIG_ENDIAN_HOST
#define MKWORD(d,n) ( (d)[8*(n)+0] << 56 | (d)[8*(n)+1] << 48 \
| (d)[8*(n)+2] << 40 | (d)[8*(n)+3] << 32 \
| (d)[8*(n)+4] << 24 | (d)[8*(n)+5] << 16 \
| (d)[8*(n)+6] << 8 | (d)[8*(n)+7] )
#define MKWORD(d,n) \
( ((u64)(d)[8*(n)+0]) << 56 | ((u64)(d)[8*(n)+1]) << 48 \
| ((u64)(d)[8*(n)+2]) << 40 | ((u64)(d)[8*(n)+3]) << 32 \
| ((u64)(d)[8*(n)+4]) << 24 | ((u64)(d)[8*(n)+5]) << 16 \
| ((u64)(d)[8*(n)+6]) << 8 | ((u64)(d)[8*(n)+7]) )
x[0] = MKWORD(data, 0);
x[1] = MKWORD(data, 1);
x[2] = MKWORD(data, 2);

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@ -1,3 +1,8 @@
Tue May 5 22:11:59 1998 Werner Koch (wk@isil.d.shuttle.de)
* keygen.c (gen_dsa): New.
* build_packet.c (do_secret_cert): Support for DSA
Mon May 4 19:01:25 1998 Werner Koch (wk@isil.d.shuttle.de)
* compress.c: doubled buffer sizes

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@ -292,6 +292,29 @@ do_secret_cert( IOBUF out, int ctb, PKT_secret_cert *skc )
mpi_write(a, skc->d.elg.x );
write_16(a, skc->csum );
}
else if( skc->pubkey_algo == PUBKEY_ALGO_DSA ) {
mpi_write(a, skc->d.dsa.p );
mpi_write(a, skc->d.dsa.q );
mpi_write(a, skc->d.dsa.g );
mpi_write(a, skc->d.dsa.y );
if( skc->is_protected ) {
iobuf_put(a, 0xff );
iobuf_put(a, skc->protect.algo );
iobuf_put(a, skc->protect.s2k.mode );
iobuf_put(a, skc->protect.s2k.hash_algo );
if( skc->protect.s2k.mode == 1
|| skc->protect.s2k.mode == 4 )
iobuf_write(a, skc->protect.s2k.salt, 8 );
if( skc->protect.s2k.mode == 4 )
write_32(a, skc->protect.s2k.count );
iobuf_write(a, skc->protect.iv, 8 );
}
else
iobuf_put(a, 0 );
mpi_write(a, skc->d.dsa.x );
write_16(a, skc->csum );
}
else if( is_RSA(skc->pubkey_algo) ) {
mpi_write(a, skc->d.rsa.n );
mpi_write(a, skc->d.rsa.e );

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@ -72,6 +72,7 @@ static ARGPARSE_OPTS opts[] = {
{ 515, "fingerprint", 0, N_("list keys and fingerprints")},
#ifdef IS_G10
{ 503, "gen-key", 0, N_("generate a new key pair")},
{ 554, "add-key", 0, N_("add a subkey to a key pair")},
{ 506, "sign-key" ,0, N_("make a signature on a key in the keyring")},
{ 505, "delete-key",0, N_("remove key from the public keyring")},
{ 524, "edit-key" ,0, N_("edit a key signature")},
@ -171,7 +172,7 @@ enum cmd_values { aNull = 0,
aSym, aStore, aEncr, aKeygen, aSign, aSignEncr,
aSignKey, aClearsign, aListPackets, aEditSig, aDeleteKey, aDeleteSecretKey,
aKMode, aKModeC, aChangePass, aImport, aVerify, aDecrypt, aListKeys,
aListSigs,
aListSigs, aKeyadd,
aExport, aCheckKeys, aGenRevoke, aPrimegen, aPrintMDs,
aListTrustDB, aListTrustPath, aDeArmor, aEnArmor, aGenRandom, aTest,
aNOP };
@ -574,6 +575,7 @@ main( int argc, char **argv )
case 551: set_cmd( &cmd, aListKeys); break;
case 552: set_cmd( &cmd, aListSigs); break;
case 553: opt.skip_verify=1; break;
case 554: set_cmd( &cmd, aKeyadd); break;
default : errors++; pargs.err = configfp? 1:2; break;
}
}
@ -817,6 +819,11 @@ main( int argc, char **argv )
wrong_args("--gen-key");
generate_keypair();
break;
case aKeyadd: /* add a subkey (interactive) */
if( argc != 1 )
wrong_args("--add-key userid");
generate_subkeypair(*argv);
break;
#endif
case aImport:
@ -873,19 +880,24 @@ main( int argc, char **argv )
putchar('\n');
}
else if( argc == 2 ) {
mpi_print( stdout, generate_elg_prime( atoi(argv[0]),
mpi_print( stdout, generate_elg_prime( 0, atoi(argv[0]),
atoi(argv[1]), NULL,NULL ), 1);
putchar('\n');
}
else if( argc == 3 ) {
MPI g = mpi_alloc(1);
mpi_print( stdout, generate_elg_prime( atoi(argv[0]),
mpi_print( stdout, generate_elg_prime( 0, atoi(argv[0]),
atoi(argv[1]), g, NULL ), 1);
printf("\nGenerator: ");
mpi_print( stdout, g, 1 );
putchar('\n');
mpi_free(g);
}
else if( argc == 4 ) {
mpi_print( stdout, generate_elg_prime( 1, atoi(argv[0]),
atoi(argv[1]), NULL,NULL ), 1);
putchar('\n');
}
else
usage(1);
break;

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@ -621,6 +621,8 @@ change_passphrase( const char *username )
break;
}
/* fixme: unprotect all subkeys */
if( rc )
tty_printf("Can't edit this key: %s\n", g10_errstr(rc));
else {
@ -648,6 +650,7 @@ change_passphrase( const char *username )
break;
}
else { /* okay */
/* fixme: protect all subkeys too */
skc->protect.algo = dek->algo;
skc->protect.s2k = *s2k;
rc = protect_secret_key( skc, dek );

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@ -224,11 +224,84 @@ gen_rsa(unsigned nbits, KBNODE pub_root, KBNODE sec_root, DEK *dek,
#endif /*ENABLE_RSA_KEYGEN*/
/****************
* Generate a DSA key
*/
static int
gen_dsa(unsigned nbits, KBNODE pub_root, KBNODE sec_root, DEK *dek,
STRING2KEY *s2k, PKT_secret_cert **ret_skc, u16 valid_days )
STRING2KEY *s2k, PKT_secret_cert **ret_skc, u16 valid_days )
{
return G10ERR_GENERAL;
int rc;
int i;
PACKET *pkt;
PKT_secret_cert *skc;
PKT_public_cert *pkc;
DSA_public_key pk;
DSA_secret_key sk;
MPI *factors;
if( nbits > 1024 )
nbits = 1024;
dsa_generate( &pk, &sk, nbits, &factors );
skc = m_alloc_clear( sizeof *skc );
pkc = m_alloc_clear( sizeof *pkc );
skc->timestamp = pkc->timestamp = make_timestamp();
skc->version = pkc->version = 4;
/* valid days are not stored in the packet, but it is
* used here to put it into the signature.
*/
skc->valid_days = pkc->valid_days = valid_days;
skc->pubkey_algo = pkc->pubkey_algo = PUBKEY_ALGO_DSA;
pkc->d.dsa.p = pk.p;
pkc->d.dsa.q = pk.q;
pkc->d.dsa.g = pk.g;
pkc->d.dsa.y = pk.y;
skc->d.dsa.p = sk.p;
skc->d.dsa.q = sk.q;
skc->d.dsa.g = sk.g;
skc->d.dsa.y = sk.y;
skc->d.dsa.x = sk.x;
skc->is_protected = 0;
skc->protect.algo = 0;
skc->csum = checksum_mpi( skc->d.dsa.x );
/* return an unprotected version of the skc */
*ret_skc = copy_secret_cert( NULL, skc );
if( dek ) {
skc->protect.algo = dek->algo;
skc->protect.s2k = *s2k;
rc = protect_secret_key( skc, dek );
if( rc ) {
log_error("protect_secret_key failed: %s\n", g10_errstr(rc) );
free_public_cert(pkc);
free_secret_cert(skc);
return rc;
}
}
pkt = m_alloc_clear(sizeof *pkt);
pkt->pkttype = PKT_PUBLIC_CERT;
pkt->pkt.public_cert = pkc;
add_kbnode(pub_root, new_kbnode( pkt ));
/* don't know whether it makes sense to have the factors, so for now
* we store them in the secret keyring (but they are not secret)
* p = 2 * q * f1 * f2 * ... * fn
* We store only f1 to f_n-1 - fn can be calculated because p and q
* are known.
*/
pkt = m_alloc_clear(sizeof *pkt);
pkt->pkttype = PKT_SECRET_CERT;
pkt->pkt.secret_cert = skc;
add_kbnode(sec_root, new_kbnode( pkt ));
for(i=1; factors[i]; i++ ) /* the first one is q */
add_kbnode( sec_root,
make_mpi_comment_node("#:DSA_factor:", factors[i] ));
return 0;
}
@ -312,7 +385,7 @@ generate_keypair()
else if( algo == 2 ) {
algo = PUBKEY_ALGO_DSA;
algo_name = "DSA";
tty_printf(_("Sorry; DSA key generation is not yet supported.\n"));
break;
}
#ifdef ENABLE_RSA_KEYGEN
else if( algo == 3 ) {
@ -380,6 +453,10 @@ generate_keypair()
" <n>w = key expires in n weeks\n"
" <n>m = key expires in n months\n"
" <n>y = key expires in n years\n"));
/* Note: The elgamal subkey for DSA has no exiration date because
* is must be signed with the DSA key and this one has the expiration
* date */
answer = NULL;
for(;;) {
int mult;
@ -578,7 +655,7 @@ generate_keypair()
rc = gen_rsa(nbits, pub_root, sec_root, dek, s2k, &skc, valid_days );
#endif
else if( algo == PUBKEY_ALGO_DSA )
rc = gen_dsa(nbits, pub_root, sec_root, dek, s2k, &skc, valid_days );
rc = gen_dsa(nbits, pub_root, sec_root, dek, s2k, &skc, valid_days);
else
BUG();
if( !rc ) {
@ -663,3 +740,13 @@ generate_keypair()
m_free(sec_fname);
}
/****************
* add a new subkey to an existing key.
*/
void
generate_subkeypair( const char *userid )
{
log_fatal("To be implemented :-)\n");
}

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@ -70,6 +70,7 @@ int change_passphrase( const char *username );
/*-- keygen.c --*/
void generate_keypair(void);
void generate_subkeypair(const char *userid);
/*-- openfile.c --*/
int overwrite_filep( const char *fname );

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@ -114,7 +114,8 @@ extern ushort small_prime_numbers[];
/*-- primegen.c --*/
MPI generate_secret_prime( unsigned nbits );
MPI generate_public_prime( unsigned nbits );
MPI generate_elg_prime( unsigned pbits, unsigned qbits, MPI g, MPI **factors );
MPI generate_elg_prime( int mode, unsigned pbits, unsigned qbits,
MPI g, MPI **factors );
#endif /*G10_CIPHER_H*/

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@ -93,7 +93,7 @@ POSUB = po
RANLIB = ranlib
USE_INCLUDED_LIBINTL = yes
USE_NLS = yes
VERSION = 0.2.17
VERSION = 0.2.17a
ZLIBS =
l =