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Serzh
Asked:2020-08-17 21:24:35 +0000 UTC2020-08-17 21:24:35 +0000 UTC

AES CBC 截断超过 16 个字符的字符串

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AES CBC 会截断长度超过 16 个字符的字符串。下次运行时，它显示 javax.crypto.BadPaddingException: Given final block not properly padded. Such issues can arise if a bad key is used during decryption.

UPD：这是有问题的代码：

public static byte[][] encrypt(String txt, String txt2, String txt3){
try {
            SecretKey mysecretKey = new SecretKeySpec("qwertyuiopasdfgh".getBytes(), "AES");
            byte[] plainText1 = txt.getBytes();
            byte[] plainText2 = txt2.getBytes();
            byte[] plainText3 = txt3.getBytes();
            byte[][] plain_bytes = new byte[][] { plainText1, plainText2, plainText3 };
            IvParameterSpec iv = new IvParameterSpec("4283810222669651".getBytes());
            cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, mysecretKey, iv);
            cipher.update(plainText1);
            byte[] cipherText1 = cipher.doFinal();
            cipher.update(plainText2);
            byte[] cipherText2 = cipher.doFinal();
            cipher.update(plainText3);
            byte[] cipherText3 = cipher.doFinal();
            byte[][] encrypted_bytes = new byte[][] { cipherText1, cipherText2, cipherText3 };
            String str = Base64.getEncoder().encodeToString(encrypted_bytes[0]);
            encryptedUrl = str;
            System.out.println(encryptedUrl);
            return encrypted_bytes;
        } catch (Exception e1) {
            e1.printStackTrace();
            return null;
    
}
    }
java

2 个回答

  1. Best Answer

    不，@Enikeyshchik，这里的一切都比较棘手。

    TC 试图通过使用多部分编码cipher.update()/doFinal()并且做错了。

    你只需要对doFinal()你的每一件作品应用这样的东西：

    cipher.init(Cipher.ENCRYPT_MODE, mysecretKey, iv);
cipherText1=cipher.doFinal(plainText1);
    • 1

  2. AES 以 128 位的块进行加密（也就是说，这些是您的 16 个字节）。错误告诉你最后一个块小于这个大小，需要填充一些东西才能达到 128 位。

    • 0

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