Mac在GCM中检查失败

Question

当我调用cipher.doFinal()方法时，返回Mac签入GCM失败

fun decrypt(key: SecretKey, input: OperationResult): Input {
        val gcmSpec = GCMParameterSpec(tagLength * 8, input.iv)
        val cipher = Cipher.getInstance(algorithmName)
        cipher.init(Cipher.DECRYPT_MODE, key, gcmSpec)
        cipher.updateAAD(input.aad)
        val data = cipher.doFinal(input.data + input.tag)
        return Input(data = data, aad = input.aad)
    }