Java3DES实现（学术）
到目前为止我的代码是：
public class TripleDES {
/**
* @param args the command line arguments
* @throws java.security.NoSuchAlgorithmException
* @throws javax.crypto.NoSuchPaddingException
* @throws java.security.InvalidKeyException
* @throws javax.crypto.IllegalBlockSizeException
* @throws javax.crypto.BadPaddingException
*/
public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
//Encrypt: C = EK3(DK2(EK1(P)))
//Decrypt: P = DK3(EK2(DK1(C)))
Scanner sc = new Scanner(System.in);
//Generate key for DES
KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
SecretKey secretKey = keyGenerator.generateKey();
SecretKey secretKey2 = keyGenerator.generateKey();
SecretKey secretKey3 = keyGenerator.generateKey();
//Text Enc & Dec
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
//enter msg
System.out.print("Enter a string: ");
String x= sc.nextLine();
//enc
cipher.init(Cipher.ENCRYPT_MODE,secretKey);
byte[] message = x.getBytes();//text
byte[] messageEnc = cipher.doFinal(message);//encryption with key1
cipher.init(Cipher.DECRYPT_MODE,secretKey2);
byte[] deck2 = cipher.doFinal(messageEnc);//decryption with key2
cipher.init(Cipher.ENCRYPT_MODE,secretKey3);
byte[] messageEnc1 = cipher.doFinal(deck2);//encryption with key3
System.out.println("Cipher Text: " + new String(messageEnc1));
//dec
cipher.init(Cipher.DECRYPT_MODE,secretKey3);
byte[] dec = cipher.doFinal(messageEnc1);//decryption with key1
cipher.init(Cipher.ENCRYPT_MODE,secretKey2);
byte[] messageEnc2 = cipher.doFinal(dec);//encryption with key2
cipher.init(Cipher.DECRYPT_MODE,secretKey);
byte[] deck3 = cipher.doFinal(messageEnc2);//decryption with key3
System.out.println("Plain Text: " + new String(deck3));
}
}
我收到错误：
Exception in thread "main" javax.crypto.BadPaddingException: Given final block not properly padded. Such issues can arise if a bad key is used during decryption.
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:991)
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:847)
at com.sun.crypto.provider.DESCipher.engineDoFinal(DESCipher.java:314)
at javax.crypto.Cipher.doFinal(Cipher.java:2164)
at tripledes.TripleDES.main(TripleDES.java:45)
我的猜测是，当我尝试在第 45 行使用不同的密钥进行解密时，会出现上述错误，这是因为加密文本大于生成的密钥，但我不太确定。
有人可以帮忙，因为我无法弄清楚问题所在。
回答
我指的是最初发布的带有cipher,cipher2和cipher3实例的代码：问题是关于cipher2and的填充cipher3。只能cipher使用PKCS5Padding，cipher2而且cipher3必须申请NoPadding。
产生的密文然后确实相同，将由3DES来生成一个，条件是级联的字节secretKey，secretKey2并且secretKey3被用作3DES密钥。
顺便说一下，欧洲央行是一种不安全的模式。在这里。
关于评论：
对于使用字符集编码对密文进行解码，请参阅例如从字节数组转换为字符串并返回到字节数组时的问题。关于缺少的编码规范，在不同的默认字符集中对 String.getBytes() 进行seg 。