Java AES GCM javax.crypto.AEADBadTagException：标签不匹配

Question

我不明白为什么我总是得到以下代码的异常：

public class AES {

    /*Some private vars (not shown)*/

    public AES(String secretKey, String initVector, String plainText, String cipherText, String addAuthData, String authTag) throws NoSuchAlgorithmException, NoSuchPaddingException {

        //Initialize test values
        this.cipher = Cipher.getInstance("AES/GCM/NoPadding");
        this.K = new SecretKeySpec(Dump.hexString2byteArray(secretKey), "AES");
        this.IV = Dump.hexString2byteArray(initVector);
        this.C = Dump.hexString2byteArray(cipherText);
        this.A = Dump.hexString2byteArray(addAuthData);
        this.T = Dump.hexString2byteArray(authTag);
        this.t = this.T.length*8;
        this.gcmIv = new GCMParameterSpec(t, IV);


    }
    public String testDecryption() throws InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {

        cipher.init(Cipher.DECRYPT_MODE, K, gcmIv);

        cipher.updateAAD(A);
        cipher.init(Cipher.DECRYPT_MODE, K, gcmIv);
        cipher.doFinal(C);
        return "Return later some string";

   }

这里是一个示例，我如何运行代码：

AES testCase4 = new AES(
            "feffe9928665731c6d6a8f9467308308", 
            "cafebabefacedbaddecaf888", 
            "d9313225f88406e5a55909c5aff5269a86a7a9531534f7da2e4c303d8a318a721c3c0c95956809532fcf0e2449a6b525b16aedf5aa0de657ba637b39", 
            "42831ec2217774244b7221b784d0d49ce3aa212f2c02a4e035c17e2329aca12e21d514b25466931c7d8f6a5aac84aa051ba30b396a0aac973d58e091", 
            "feedfacedeadbeeffeedfacedeadbeefabaddad2", 
            "5bc94fbc3221a5db94fae95ae7121a47"
        );

        String TC4_p = testCase4.testDecryption();

有人可以解释一下吗？错误来自 cipher.doFinal(C);

行

Answer 1

您的源代码中有 2 个问题。在本机 Java 中，身份验证标记 ("authTag") 与密文 ("C") 连接在一起，因此 class 的初始化应该是

this.C = Dump.hexString2byteArray(cipherText + authTag);

其次，在 test.Decryption 中，您将密码初始化两次，省略 second 行

cipher.init(Cipher.DECRYPT_MODE, K, gcmIv);

这样解密就可以正常工作了

"d9313225f88406e5a55909c5aff5269a86a7a9531534f7da2e4c303d8a318a721c3c0c95956809532fcf0e2449a6b525b16aedf5aa0de657ba637b39"

Java AES GCM javax.crypto.AEADBadTagException：标签不匹配

Java AES GCM javax.crypto.AEADBadTagException: Tag mismatch

java

aes