I need 64bit integers to seed some PRNG work I'm doing. I found out that you can easily create four 64bit numbers from any string by using SHA256.

use Digest::SHA;

my $input = $ARGV[0] || int(rand() * 1000000);

# Get raw bytes and convert to an array of uint64_t
my $hash = Digest::SHA::sha256($input);
my @nums = unpack("Q*", $hash);

print "SHA256 Hashing '$input' to: " . join(", ", @nums) . "\n";

Note: We are using sha256 here, not sha256_hex because we need raw bytes.