#!/usr/bin/perl
    local ($buffer, @pairs, $pair, $name, $value, %FORM);
    # Read in text
    $ENV{'REQUEST_METHOD'} =~ tr/a-z/A-Z/;
    if ($ENV{'REQUEST_METHOD'} eq "POST")
    {
        read(STDIN, $buffer, $ENV{'CONTENT_LENGTH'});
    }else {
        $buffer = $ENV{'QUERY_STRING'};
    }
    # Split information into name/value pairs
    @pairs = split(/&/, $buffer);
    foreach $pair (@pairs)
    {
        ($name, $value) = split(/=/, $pair);
        $value =~ tr/+/ /;
        $value =~ s/%(..)/pack("C", hex($1))/eg;
        $FORM{$name} = $value;
    }
   my $old_pass = $FORM{oldpass};
   my $new_pass = $FORM{newpass1};
   my $new_pass2 = $FORM{newpass2};

print "Content-type:text/html\r\n\r\n";
use CGI;
use warnings;
use strict;
use Crypt::CBC;
my $KEY = 'secrect_foo';

        my $readfile ="pass.txt";

        open (my $passfile, '<', $readfile) or die "could not open file";
        my $readpass = do{ local $/; <$passfile> };

#        print "Reading pass from file: $readpass\n";

        close ($passfile);


my $dec = decryptString($readpass);

        if($dec eq $old_pass)
                {
                print "<h2>Password Matched<h2>\n";

                if($new_pass eq $new_pass2)
                {
                        my $enc = encrypString($new_pass);

                        print "encrypted binary: $enc\n";

                        my $storedpassfile = 'pass.txt';
                        open(my $fh, '>', $storedpassfile) or die "Could not open the pass file";
                        print $fh "$enc";
                        close $fh;

                        print "New Password Updated\n";
                        }
                else {
                        print "New pass & Confirm Pass is not same";
                        }

        }
        else{
                        print "Old Pass & Stored Pass mismatch\n";
        }



sub encrypString {
        my $string = shift;
        my $cipher = Crypt::CBC->new(
                -key    => $KEY,
                -cipher => 'Blowfish',
                -padding => 'space',
                -add_header => 1
        );

        my $enc = $cipher->encrypt($string);
        return $enc;
}


sub decryptString {
        my $string = shift;
        my $cipher = Crypt::CBC->new(
                -key    => $KEY,
                -cipher => 'Blowfish',
                -padding => 'space',
                -add_header => 1
        );

        my $dec = $cipher->decrypt($string);
        return $dec;
}