// EncryptedDEKSource is the ciphertext of the source of the DEK used to encrypt the data stored in encryptedData.
  // encryptedDEKSourceType defines the process of using the plaintext of this field to determine the aforementioned DEK.
  // encryptedDEKSource must satisfy the following constraints:
  // 1. The encrypted DEK source is not empty.
  // 2. The size of encrypted DEK source is less than 1 kB.
  bytes encryptedDEKSource = 3;

	// EncryptedDEKSource is the ciphertext of the source of the DEK used to encrypt the data stored in encryptedData.
	// encryptedDEKSourceType defines the process of using the plaintext of this field to determine the aforementioned DEK.
	// encryptedDEKSource must satisfy the following constraints:
	// 1. The encrypted DEK source is not empty.
	// 2. The size of encrypted DEK source is less than 1 kB.

	dek, err := c.client.GenerateKey(ctx, name, aad)
	if err != nil {
		if errors.Is(err, kes.ErrKeyNotFound) {
			return DEK{}, ErrKeyNotFound
		}
		if errors.Is(err, kes.ErrNotAllowed) {
			return DEK{}, ErrPermission
		}
		return DEK{}, errKeyGenerationFailed(err)
	}
	return DEK{
		KeyID:      name,
		Plaintext:  dek.Plaintext,
		Ciphertext: dek.Ciphertext,
	}, nil
}

	password []byte
	pemData  []byte
	plainDER string
}{
	{
		kind:     PEMCipherDES,
		password: []byte("asdf"),
		pemData: []byte(testingKey(`
-----BEGIN RSA TESTING KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-CBC,34F09A4FC8DE22B5

WXxy8kbZdiZvANtKvhmPBLV7eVFj2A5z6oAxvI9KGyhG0ZK0skfnt00C24vfU7m5
ICXeoqP67lzJ18xCzQfHjDaBNs53DSDT+Iz4e8QUep1xQ30+8QKX2NA2coee3nwc
6oM1cuvhNUDemBH2i3dKgMVkfaga0zQiiOq6HJyGSncCMSruQ7F9iWEfRbFcxFCx

// name of the secretKey.
//
// The returned DEK is encrypted using AES-GCM and the ciphertext format is compatible
// with KES and MinKMS.
func (s secretKey) GenerateKey(_ context.Context, req *GenerateKeyRequest) (DEK, error) {
	if req.Name != s.keyID {
		return DEK{}, ErrKeyNotFound
	}
	associatedData, err := req.AssociatedData.MarshalText()
	if err != nil {
		return DEK{}, err
	}

	const randSize = 28

func DecryptPEMBlock(b *pem.Block, password []byte) ([]byte, error) {
	dek, ok := b.Headers["DEK-Info"]
	if !ok {
		return nil, errors.New("x509: no DEK-Info header in block")
	}

	mode, hexIV, ok := strings.Cut(dek, ",")
	if !ok {
		return nil, errors.New("x509: malformed DEK-Info header")
	}

	ciph := cipherByName(mode)
	if ciph == nil {

var dekEncodeDecodeTests = []struct {
	Key DEK
}{
	{
		Key: DEK{},
	},
	{
		Key: DEK{
			Plaintext:  nil,
			Ciphertext: mustDecodeB64("eyJhZWFkIjoiQUVTLTI1Ni1HQ00tSE1BQy1TSEEtMjU2IiwiaXYiOiJ3NmhLUFVNZXVtejZ5UlVZL29pTFVBPT0iLCJub25jZSI6IktMSEU3UE1jRGo2N2UweHkiLCJieXRlcyI6Ik1wUkhjQWJaTzZ1Sm5lUGJGcnpKTkxZOG9pdkxwTmlUcTNLZ0hWdWNGYkR2Y0RlbEh1c1lYT29zblJWVTZoSXIifQ=="),
		},
	},
	{
		Key: DEK{

	}{
		{
			name:               "encrypted DEK source is nil",
			encryptedDEKSource: nil,
			expectedError:      "encrypted DEK source is empty",
		},
		{
			name:               "encrypted DEK source is empty",
			encryptedDEKSource: []byte{},
			expectedError:      "encrypted DEK source is empty",
		},
		{
			name:               "encrypted DEK source size is greater than 1 kB",

	// not exist.
	//
	// The context is associated and tied to the generated DEK.
	// The same context must be provided when the generated key
	// should be decrypted. Therefore, it is the callers
	// responsibility to remember the corresponding context for
	// a particular DEK. The context may be nil.
	GenerateKey(context.Context, *GenerateKeyRequest) (DEK, error)

	// DecryptKey decrypts the ciphertext with the key referenced

// 1. The encrypted DEK source is not empty.
// 2. The size of encrypted DEK source is less than 1 kB.
func validateEncryptedDEKSource(encryptedDEKSource []byte) error {
	if len(encryptedDEKSource) == 0 {
		return fmt.Errorf("encrypted DEK source is empty")
	}
	if len(encryptedDEKSource) > encryptedDEKSourceMaxSize {