class ActiveSupport::MessageVerifier

def get_data_and_digest_from(signed_message)
  return if signed_message.nil? || !signed_message.valid_encoding? || signed_message.empty?
  separator_index = separator_index_for(signed_message)
  return if separator_index.nil?
  data = signed_message[0...separator_index]
  digest = signed_message[separator_index + SEPARATOR_LENGTH..-1]
  [data, digest]
end