for i, test := range dekEncodeDecodeTests {
		text, err := test.Key.MarshalText()
		if err != nil {
			t.Fatalf("Test %d: failed to marshal DEK: %v", i, err)
		}

		var key DEK
		if err = key.UnmarshalText(text); err != nil {
			t.Fatalf("Test %d: failed to unmarshal DEK: %v", i, err)
		}
		if key.Plaintext != nil {
			t.Fatalf("Test %d: unmarshaled DEK contains non-nil plaintext", i)
		}

	}
	return json.Marshal(JSON{
		KeyID:      d.KeyID,
		Ciphertext: d.Ciphertext,
	})
}

// UnmarshalText tries to decode text as JSON representation
// of a DEK and sets DEK's key ID and ciphertext to the
// decoded values.
//
// It sets DEK's plaintext to nil.
func (d *DEK) UnmarshalText(text []byte) error {
	type JSON struct {
		KeyID      string `json:"keyid"`
		Ciphertext []byte `json:"ciphertext"`