#!/usr/bin/perl

## Remove this when errors are resolved
use diagnostics -verbose; #print warning diagnostics
use CGI qw(:standard);
use CGI::Carp qw(fatalsToBrowser);

use Convert::PEM;
use Crypt::OpenSSL::RSA;
use MIME::Base64;
use strict;

my $private_key = '/path/to/privatekey.pem';

my $encrypted_string =q(encrypted string_1 value);

my $password = 'OurPassword';

my $key = decryptPrivate($private_key,$password,$encrypted_string);

print "Content-type: text/html\n\n";	
print "$key<br>";	

exit;


sub decryptPrivate {
  my ($private_key,$password,$string) = @_;
  my $key_string = readPrivateKey($private_key,$password);

  return(undef) unless ($key_string); # Decrypt failed.
  my $private = Crypt::OpenSSL::RSA->new_private_key($key_string) ||
  die "$!";

  $private->decrypt(decode_base64($string));
  #$private->decrypt($string);
}

sub readPrivateKey {
  my ($file,$password) = @_;
  my $key_string;
  $key_string = decryptPEM($file,$password);
}

sub decryptPEM {
  my ($file,$password) = @_;

  my $pem = Convert::PEM->new(
                              Name => 'RSA PRIVATE KEY',
                              ASN  => qq(
                  RSAPrivateKey SEQUENCE {
                      version INTEGER,
                      n INTEGER,
                      e INTEGER,
                      d INTEGER,
                      p INTEGER,
                      q INTEGER,
                      dp INTEGER,
                      dq INTEGER,
                      iqmp INTEGER
                  }
           ));


  my $pkey = $pem->read(Filename => $file, Password => $password);

  return(undef) unless ($pkey); # Decrypt failed.
  $pem->encode(Content => $pkey);
}