gen-private-key

#!/usr/bin/env perl
use strict;
use warnings;
use bignum;
use Crypt::OpenSSL::Bignum;
use Crypt::OpenSSL::RSA;

my $n = shift;
my $p = shift;
my $q = shift or die "Usage: $0 n p q [e]\n";
my $e = shift || 0x10001;
$n = guess_dec_hex($n);
$p = guess_dec_hex($p);
$q = guess_dec_hex($q);
$e = guess_dec_hex($e);

$n = Crypt::OpenSSL::Bignum->new_from_decimal($n);
$p = Crypt::OpenSSL::Bignum->new_from_decimal($p);
$q = Crypt::OpenSSL::Bignum->new_from_decimal($q);
$e = Crypt::OpenSSL::Bignum->new_from_decimal($e);

my $rsa = Crypt::OpenSSL::RSA->new_key_from_parameters($n, $e, undef, $p, $q);
print $rsa->get_private_key_string();

sub guess_dec_hex {
    my $n = shift;
    if ($n =~ s/^0x//) {
        $n = hex $n;
    }
    return $n;
}