#!/usr/bin/perl
use Crypt::OpenSSL::Random;
use Crypt::OpenSSL::RSA;
use Crypt::OpenSSL::X509;
use MIME::Base64;
use strict;

my $debug = 0;
local $/ = undef;

my $public_key= "/data/pubkey.pem";
open (FILE, $public_key) or die ("Cant open public key file");
my $public_key_string = <FILE>;
close(FILE);

my $private_key = "/data/private.pem";
open (FILE, $private_key) or die ("Cant open private key file");
my $private_key_string = <FILE>;
close(FILE);

my $public_cert = "/data/x509-public.pem";
open (FILE, $public_cert) or die ("Cant open certificate file");
my $certificate = <FILE>;
close(FILE);

print $certificate;
my $cert = Crypt::OpenSSL::X509->new_from_string($certificate);
print $cert->pubkey;
print $public_key_string; # they're different

$public_key_string=$cert->pubkey; # it's different to the one loaded from file, but still works with my existing private key in the rest of the code - remove this line to test the old $public_key_string value
print $public_key_string; 

my $plaintext = "Some text here";

my $rsa_pub  = Crypt::OpenSSL::RSA->new_public_key($public_key_string);
my $rsa_priv = Crypt::OpenSSL::RSA->new_private_key($private_key_string);

my $ciphertext     =  $rsa_pub->encrypt($plaintext); # encrypt with the public key
my $plaintext_back =  $rsa_priv->decrypt($ciphertext); # decrypt with the private key

print "Plain text back is " . $plaintext_back . "\n"; # Works fine

if ($debug){ # debugging only
        print "private key is:\n", $rsa_priv->get_private_key_string();
        print "public key (in PKCS1 format) is:\n",
        $rsa_pub->get_public_key_string();
        print "public key (in X509 format) is:\n",
        $rsa_pub->get_public_key_x509_string();
}

$rsa_priv->use_md5_hash(); # use_sha1_hash is the default
$rsa_pub->use_md5_hash();

my $signature = $rsa_priv->sign($plaintext); # sign with private key

if ($rsa_pub->verify($plaintext, $signature)) { # verify with public key
        print "Signature Verified successfully";
} else {
        print " *** Not verified";
}