We can provide better random bytes than these other modules,
and fortunately someone gave us a way to get to arc4random_buf from perl.

Index: lib/Crypt/OpenPGP/Util.pm
--- lib/Crypt/OpenPGP/Util.pm.orig
+++ lib/Crypt/OpenPGP/Util.pm
@@ -4,6 +4,8 @@ use strict;
 # For some reason, FastCalc causes problems. Restrict to one of these 3 backends
 use Math::BigInt only => 'Pari,GMP,Calc';
 
+use Unix::OpenBSD::Random qw( arc4random_buf );
+
 use vars qw( @EXPORT_OK @ISA );
 use Exporter;
 @EXPORT_OK = qw( bitsize bin2bigint bin2mp bigint2bin mp2bin mod_exp mod_inverse
@@ -101,6 +103,8 @@ sub _ensure_bigint {
 
 sub get_random_bytes {
 	my $length = shift;
+	return arc4random_buf($length);
+
 	if (eval 'require Crypt::Random; 1;') {
 		return Crypt::Random::makerandom_octet( Length => $length);
 	}
@@ -114,6 +118,15 @@ sub get_random_bytes {
 
 sub get_random_bigint {
 	my $bits = shift;
+
+	my $hex = unpack "H*", arc4random_buf( int(($bits + 7) / 8) );
+	my $val = Math::BigInt->new("0x$hex");
+	# Get exactly the correct number of bits.
+	$val->brsft(8 - ($bits & 7)) if ($bits & 7);
+	# Make sure the top bit is set.
+	$val->bior(Math::BigInt->bone->blsft($bits-1));
+	return $val;
+
 	if (eval 'require Crypt::Random; 1;') {
 		my $pari = Crypt::Random::makerandom( Size => $bits, Strength => 0 );
 		return Math::BigInt->new($pari);