4J

I discovered that the Perl Crypt::Blowfish library could only encrypt 8-byte long strings. This is obviously not good in any practical way. So, I experimented, and came up with the following concept program. At the end, it also uses MIME::Base64::URLSafe to make the encrypted string portable - especially for the web.

#!/usr/bin/perl

use strict;

use MIME::Base64::URLSafe; # Used to encode our parameter string
use Crypt::Blowfish;  # All our parameters and cookies will be blowfish encrypted


my $crypt_key = pack("H16", "1234567890ABCDEF"); # min. 8 bytes
my $str  = $ARGV[0];    # Get out str to encrypt and encode


my $encoded_str = encrypt_long_str( $crypt_key, $str );
print "\n-----------------------------------------------\n$encoded_str\n-----------------------------------------------\n\n";


my $decoded_str = decrypt_long_str(  $crypt_key, $encoded_str );
print "\n-----------------------------------------------\n$decoded_str\n-----------------------------------------------\n\n";


exit;

#######################################
#
# S U B S
#
#######################################

sub encrypt_long_str {

my( $key, $str ) = @_;

my $strlen  = length( $str );
my $encrypted  = "";
my $encoded  = "";
my $parts  = 0;

my $cipher   = new Crypt::Blowfish $key;

# calculate the parts
while( length( $str ) ) {

 if( length( $str ) < style="color: rgb(68, 68, 255);">) {

  while( length( $str ) < style="color: rgb(68, 68, 255);">) {

   $str .= " ";

  }

  my $raw  = $cipher->encrypt( $str );
  my $encoded1 = urlsafe_b64encode( $raw );

  print STDERR "\tdebug: encrypt_long_str(): encoded_part=$encoded1\n";

  $encoded .= $encoded1;

  $str  = "";
  $parts++;

 } else {

  my $tstr = substr( $str, 0, 8 );
  my $raw         = $cipher->encrypt( $tstr );
  my $encoded1    = urlsafe_b64encode( $raw );

  print STDERR "\tdebug: encrypt_long_str(): encoded_part=$encoded1\n";

  $encoded        .= $encoded1;

  $str  =~ s/^$tstr//;
  $parts++;

 }

}

if( $parts < 10 ) { $encoded = "000" . $parts . $encoded; }

elsif( $parts > 9 && $parts < 100 ) { $encoded = "00" . $parts . $encoded; }

elsif( $parts > 99 && $parts < 1000 ) { $encoded = "0" . $parts . $encoded; }

else { $encoded = $parts . $encoded; }

return $encoded;


}

sub decrypt_long_str {

my( $key, $str )        = @_;
my $cipher              = new Crypt::Blowfish $key;

my $retval  = "";

$str   =~ s/^(\d\d\d\d)//;
my $parts  = $1;
$parts   =~ s/^0+//;

print STDERR "\tdebug: decrypt_long_str(): parts=$parts\n";

my $steps  = length( $str )  / $parts;

print STDERR "\tdebug: decrypt_long_str(): steps_length=$steps\n";

for( my $step = 0; $step < $parts; $step++ ) {

 my $substr = substr( $str, ( $step * $steps ), $steps );
 my $dec  = urlsafe_b64decode( $substr );

 print STDERR "\tdebug: decrypt_long_str(): substr=$substr\n";

 my $dstr = $cipher->decrypt( $dec );

 $retval  .= $dstr;

 print STDERR "\tdebug: decrypt_long_str(): decrypted part $step :: $dstr\n";

}

# Remove any trailing spaces
$retval   =~ s/\s+$//;

return $retval;

}

I hope you find it usefull

# posted by Nico @ 11:10