This is fast and simple realization for encrypt/decrypt RSA. Require Math::Pari. This is only encrypt/decrypt without keys generation. I'm use OpenSSL for key generation:
openssl genrsa 1024 | openssl rsa -text >RSA.keys
And this code encrypt/decrypt only numeric messages.
{ use Math::Pari qw(PARI Mod lift); my ($n, $e, $d);
sub RSA_encrypt { lift Mod($_[0], $n) ** $e }
sub RSA_decrypt { lift Mod($_[0], $n) ** $d }
sub RSA_read_keys {
    my ($filename) = @_;
    local (*F, $/);
        open F, $filename or die $!; my $keys=<F>; close F;
    my @n = map{int hex}split /[\s:]+/,
        join"",$keys=~/modulus:\n((?:\s.*\n)+)/;
    $e = join"",$keys=~/publicExponent: (\d+).*\n/;
    my @d = map{int hex}split /[\s:]+/,
        join"",$keys=~/privateExponent:\n((?:\s.*\n)+)/;
    my $base = PARI 256; $n = PARI 0; $d = PARI 0;
    $n += ($base ** $#n) * shift @n while @n;
    $d += ($base ** $#d) * shift @d while @d;
}}
print "Reading keys...\n";
RSA_read_keys("RSA.keys");
$msg = "1020304050";
print "Encrypting: $msg\n";
$enc = RSA_encrypt($msg);
print "Encrypted: $enc\n";
$dec = RSA_decrypt($enc);
print "Decrypted: $dec\n";

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In reply to Using RSA (simple) by powerman

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