What are best practices for working with signing and verification?

# Example of signing and verifying a message in Perl
    
use strict;
use warnings;
use Crypt::OpenSSL::RSA;
use MIME::Base64;

my $private_key_file = 'private.pem'; # Path to your private key
my $public_key_file = 'public.pem';   # Path to your public key
my $message = "This is a secret message";

# Load private key for signing
my $private_key = Crypt::OpenSSL::RSA->new_private_from_pem(file($private_key_file));
my $signature = $private_key->sign($message);

# Encode signature to base64 for transmission
my $encoded_signature = encode_base64($signature);

# Load public key for verification
my $public_key = Crypt::OpenSSL::RSA->new_public_from_pem(file($public_key_file));
my $is_verified = $public_key->verify($message, decode_base64($encoded_signature));

if ($is_verified) {
    print "Signature verified successfully!\n";
} else {
    print "Signature verification failed.\n";
}

sub file {
    my $filename = shift;
    local @ARGV = ($filename);
    return <>;
}