class Aws::S3::EncryptionV2::DecryptHandler

def extract_envelope(hash)
  return nil unless hash
  return v1_envelope(hash) if hash.key?('x-amz-key')
  return v2_envelope(hash) if hash.key?('x-amz-key-v2')
  if hash.keys.any? { |key| key.match(/^x-amz-key-(.+)$/) }
    msg = "unsupported envelope encryption version #{$1}"
    raise Errors::DecryptionError, msg
  end
end