}

// New returns a single-key KMS that derives new DEKs from the
// given key.
func New(keyID string, key []byte) (KMS, error) {
	if len(key) != 32 {
		return nil, errors.New("kms: invalid key length " + strconv.Itoa(len(key)))
	}
	return secretKey{
		keyID: keyID,
		key:   key,
	}, nil
}

// secretKey is a KMS implementation that derives new DEKs
// from a single key.
type secretKey struct {
	keyID string