SES SMTP password generation

#!/usr/bin/ruby
require 'openssl'
require 'base64'

sha256 = OpenSSL::Digest::Digest.new('sha256')
secret_key = "Secret Access Key"
message = "SendRawEmail"
version = "\x02"

signature = OpenSSL::HMAC.digest(sha256, secret_key, message)
verSignature = version + signature

smtp_password = Base64.encode64(verSignature)
puts smtp_password