##############  gen_keys  ####################
#!/usr/bin/perl
use warnings;
use strict;
use Crypt::DSA;
use Crypt::DSA::Key;

#  script to generate keys

my $dsa = Crypt::DSA->new;

# use to generate your keys below 
# multiple of 512, 1024, 2048, 4096(long time) 
 my $key = $dsa->keygen(Size => 512, Verbosity => 1);
# print ref $key,"\n";  
# foreach my $k (keys %{$key}) {  
# print $k . "=" . $key->$k . "\n\n ";  
# } 

# hard code in the above generated numbers. 
my %key_priv;
 $key_priv{'priv_key'} = $key->{'priv_key'};
 $key_priv{'p'} =  $key->{'p'};
 $key_priv{'g'} = $key->{'g'};
 $key_priv{'q'} = $key->{'q'};
# $key_priv{'pub_key'} = ''; #don't include in private key  

my %key_pub;
# $key_pub{'priv_key'} = ''; #don't include in public key  
 $key_pub{'p'} = $key->{'p'};
 $key_pub{'g'} = $key->{'g'};
 $key_pub{'q'} = $key->{'q'};
 $key_pub{'pub_key'} = $key->{'pub_key'};

#private key file 
my $k_priv = \%key_priv;
bless($k_priv, "Crypt::DSA::Key");

my $pem_priv = $k_priv->write( Type => 'PEM' );
open(FH,">key_priv") or die "$!\n";
print FH $pem_priv;
close FH;

#public key file 
my $k_pub = \%key_pub;
bless($k_pub, "Crypt::DSA::Key");

my $pem_pub = $k_pub->write( Type => 'PEM' );
open(FH,">key_pub") or die "$!\n";
print FH $pem_pub;
close FH;
__END__
############################################



############# sign-a-file #######################
#!/usr/bin/perl
use warnings;
use strict;
use Crypt::DSA;
use Crypt::DSA::Key;
use MIME::Base64 qw( encode_base64 decode_base64 );

#  sample script to sign a file named 'msg'

my $dsa = Crypt::DSA->new;

my $msg_in;
open (FH,"< msg");
read( FH, $msg_in, -s FH );
close FH;

my $key_priv = Crypt::DSA::Key->new( Type => 'PEM',
                        Filename => 'key_priv');

my $sig = $dsa->sign(Message=> $msg_in,
                     Key => $key_priv);

my $sig_ser = $sig->serialize;
open(FH,">sig") or die "$!\n";
print FH encode_base64($sig_ser); #need base64 encoding 
close FH;                         #of binary sig 

__END__
#############################################



############ verify-a-file #########################

#!/usr/bin/perl
use warnings;
use strict;
use Crypt::DSA;
use Crypt::DSA::Key;
use MIME::Base64 qw( encode_base64 decode_base64 );

# sample script to verify a file named 'msg' with sig in 'sig'

my $msg_in;
open (FH,"< msg");
read( FH, $msg_in, -s FH );
close FH;

my $key_pub = Crypt::DSA::Key->new( Type => 'PEM',
                        Filename => 'key_pub');

my $sig_in;
open (FH,"< sig");
read( FH, $sig_in, -s FH );
close FH;

my $dsa = Crypt::DSA->new;

my $sig_o = Crypt::DSA::Signature->new(
            Content => decode_base64( $sig_in )
            );

my $verified = $dsa->verify(
     Message   => $msg_in,
     Signature => $sig_o,
     Key       => $key_pub,
);
print "verified thru files->$verified\n";
__END__
###########################################
## 


#########  check-key ########################

#!/usr/bin/perl
use warnings;
use strict;
use Crypt::DSA;
use Crypt::DSA::Key;

# script to make sure public key dosn't contain priv_key   
#  so it isn't distributed accidently 

my $key = Crypt::DSA::Key->new( Type => 'PEM',
                        Filename => 'key_pub');

 print ref $key,"\n";
 foreach my $k (keys %{$key}) {
   next if $k eq '__pem';
   print $k . "=" . $key->{$k} . "\n\n ";

 }

__END__
#############################################
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