algorithm = algorithmAESGCM
	} else {
		algorithm = algorithmChaCha20Poly1305
	}

	var aead cipher.AEAD
	switch algorithm {
	case algorithmAESGCM:
		mac := hmac.New(sha256.New, kms.key)
		mac.Write(iv)
		sealingKey := mac.Sum(nil)

		var block cipher.Block
		block, err = aes.NewCipher(sealingKey)
		if err != nil {
			return DEK{}, err
		}
		aead, err = cipher.NewGCM(block)