Make an SMTP password from an access secret key and a region name for Amazon SES

make-amazon-ses-smtp-password.pl

#!/usr/bin/env perl
use strict;
use warnings;
use MIME::Base64;
use Digest::SHA;

my $secret = shift or die('The 1st argument should be an access secret key');
my $region = shift or die('The 2nd argument should be a valid region name');
my $params = {
    'date'      => '11111111',
    'service'   => 'ses',
    'message'   => 'SendRawEmail',
    'terminal'  => 'aws4_request',
    'version'   => "\x04",
};

my $digest = makedigest('AWS4'.$secret, $params->{'date'});
   $digest = makedigest($digest, $region);
   $digest = makedigest($digest, $params->{'service'});
   $digest = makedigest($digest, $params->{'terminal'});
   $digest = makedigest($digest, $params->{'message'});
printf("%s\n", MIME::Base64::encode_base64(sprintf("%s%s", $params->{'version'}, $digest), ''));

sub makedigest {
    my $key = shift // return undef;
    my $msg = shift // return undef;
    return Digest::SHA::hmac_sha256($msg, $key);
}