做PBKDF2WithHmacSHA256 + AES/GCM/NoPadding的最小例子抛出：javax.crypto.AEADBadTagException：mac检查GCM失败

Question

我写了这个Java的加密和解密的最小例子，使用Bouncy Castle，PBKDF2WithHmacSHA256从派生键密码和AES/GCM/NoPadding加密/验证有效载荷：

import org.bouncycastle.jce.provider.BouncyCastleProvider; 
import org.bouncycastle.util.encoders.Base64; 
import tech.dashman.dashman.crypto.Util; 

import javax.crypto.Cipher; 
import javax.crypto.SecretKey; 
import javax.crypto.SecretKeyFactory; 
import javax.crypto.spec.IvParameterSpec; 
import javax.crypto.spec.PBEKeySpec; 
import java.security.SecureRandom; 
import java.security.Security; 
import java.util.Arrays; 

public class Scratch { 
    public static void main(String[] args) throws Exception { 
     Security.insertProviderAt(new BouncyCastleProvider(), 1); 

     String password = "password"; 
     String payload = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aenean in tincidunt metus. Nam nec diam sed velit blandit porta quis et augue. Praesent imperdiet, nulla vel aliquam porta, dui nisi dictum justo, pellentesque elementum purus orci at leo. Duis scelerisque, urna sit amet fringilla interdum, mauris felis sagittis eros, eleifend tincidunt risus nulla ut erat. Aliquam id sapien non neque rutrum lacinia at vitae lorem. Vivamus quis ligula nunc. Aenean facilisis pretium leo, vitae gravida quam ultrices et. Ut venenatis eros in justo semper fermentum. Pellentesque convallis lectus urna, fringilla rhoncus metus faucibus quis. Sed eu rhoncus tortor. Donec lacinia tempor elementum."; 

     int keyLength = 256; 
     int saltLength = keyLength/8; // It's bytes, not bits. 
     int iterations = 65536; 

     byte[] salt = new SecureRandom().generateSeed(saltLength); 
     PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray(), salt, iterations, keyLength); 
     SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256", "BC"); 
     SecretKey passwordKey = secretKeyFactory.generateSecret(keySpec); 

     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding", "BC"); 
     cipher.init(Cipher.ENCRYPT_MODE, passwordKey); 
     byte[] iv = cipher.getIV(); 
     System.out.println(Arrays.toString(cipher.getIV())); 
     byte[] cipherText = cipher.doFinal(payload.getBytes()); 

     System.out.println(Base64.toBase64String(cipherText)); 

     keySpec = new PBEKeySpec(password.toCharArray(), salt, iterations, keyLength); 
     secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256", "BC"); 
     passwordKey = secretKeyFactory.generateSecret(keySpec); 

     cipher = Cipher.getInstance("AES/GCM/NoPadding", "BC"); 
     cipher.init(Cipher.DECRYPT_MODE, passwordKey, new IvParameterSpec(iv)); 
     System.out.println(Arrays.toString(cipher.getIV())); 
     byte[] plainText = cipher.doFinal(payload.getBytes()); 
     System.out.println(new String(plainText)); 
    } 
} 

但它不工作。我得到这个例外：

Exception in thread "main" javax.crypto.AEADBadTagException: mac check in GCM failed 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) 
    at org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher$AEADGenericBlockCipher.doFinal(Unknown Source) 
    at org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher.engineDoFinal(Unknown Source) 
    at javax.crypto.Cipher.doFinal(Cipher.java:2165) 
    at tech.dashman.dashman.Scratch.main(Scratch.java:51) 

我已经验证，以防万一，这两个密码的init矢量是相同的。我还有什么遗漏？

Answer 1

您试图解密明文而不是密文。在倒数第二行：

byte[] plainText = cipher.doFinal(payload.getBytes()); 

应该是：

byte[] plainText = cipher.doFinal(cipherText);