如何在Java中使用3DES加密/解密？

Question

如何在Java中使用3DES加密/解密？

我编写的每个使用3DES在Java中编码字符串的方法都无法解密回原始字符串.有没有人有一个简单的代码片段,只能编码,然后将字符串解码回原始字符串？

我知道我在这段代码中某处犯了一个非常愚蠢的错误.以下是我到目前为止一直在使用的内容:

**注意,我没有从encrypt方法返回BASE64文本,而且我在解密方法中不是base64 un-encoding,因为我试图看看我是否在BASE64部分拼图中犯了错误.

public class TripleDESTest {

    public static void main(String[] args) {

        String text = "kyle boon";

        byte[] codedtext = new TripleDESTest().encrypt(text);
        String decodedtext  = new TripleDESTest().decrypt(codedtext);

        System.out.println(codedtext);
        System.out.println(decodedtext);
    }

    public byte[] encrypt(String message) {
        try {
            final MessageDigest md = MessageDigest.getInstance("md5");
            final byte[] digestOfPassword = md.digest("HG58YZ3CR9".getBytes("utf-8"));
            final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
            for (int j = 0,  k = 16; j < 8;)
            {
                keyBytes[k++] = keyBytes[j++];
            }

            final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
            final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
            final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key, iv);

            final byte[] plainTextBytes = message.getBytes("utf-8");
            final byte[] cipherText = cipher.doFinal(plainTextBytes);
            final String encodedCipherText = new sun.misc.BASE64Encoder().encode(cipherText);

            return cipherText;    
        }
        catch (java.security.InvalidAlgorithmParameterException e) { System.out.println("Invalid Algorithm"); }
        catch (javax.crypto.NoSuchPaddingException e) { System.out.println("No Such Padding"); }
        catch (java.security.NoSuchAlgorithmException e) { System.out.println("No Such Algorithm"); }
        catch (java.security.InvalidKeyException e) { System.out.println("Invalid Key"); }
        catch (BadPaddingException e) { System.out.println("Invalid Key");}
        catch (IllegalBlockSizeException e) { System.out.println("Invalid Key");}
        catch (UnsupportedEncodingException e) { System.out.println("Invalid Key");}

        return null;
    }

    public String decrypt(byte[] message) {
        try
        {
            final MessageDigest md = MessageDigest.getInstance("md5");
            final byte[] digestOfPassword = md.digest("HG58YZ3CR9".getBytes("utf-8"));
            final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
            for (int j = 0,  k = 16; j < 8;)
            {
                keyBytes[k++] = keyBytes[j++];
            }

            final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
            final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
            final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
            decipher.init(Cipher.DECRYPT_MODE, key, iv);

            //final byte[] encData = new sun.misc.BASE64Decoder().decodeBuffer(message);
            final byte[] plainText = decipher.doFinal(message);

            return plainText.toString();            
        }
        catch (java.security.InvalidAlgorithmParameterException e) { System.out.println("Invalid Algorithm"); }
        catch (javax.crypto.NoSuchPaddingException e) { System.out.println("No Such Padding"); }
        catch (java.security.NoSuchAlgorithmException e) { System.out.println("No Such Algorithm"); }
        catch (java.security.InvalidKeyException e) { System.out.println("Invalid Key"); }
        catch (BadPaddingException e) { System.out.println("Invalid Key");}
        catch (IllegalBlockSizeException e) { System.out.println("Invalid Key");}
        catch (UnsupportedEncodingException e) { System.out.println("Invalid Key");}     
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;
    }
}

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Answer 1

Bor*_*zic 64

您的代码很好,除了Base 64编码位(您提到的是测试),输出可能没有意义的原因是您显示的是原始字节数组(在字节数组上执行toString()返回其内部Java引用,不是的字符串表示的内容).这是一个只有少量清理的版本,它打印出"kyle boon"作为解码后的字符串:

import java.security.MessageDigest;
import java.util.Arrays;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class TripleDESTest {

    public static void main(String[] args) throws Exception {

        String text = "kyle boon";

        byte[] codedtext = new TripleDESTest().encrypt(text);
        String decodedtext = new TripleDESTest().decrypt(codedtext);

        System.out.println(codedtext); // this is a byte array, you'll just see a reference to an array
        System.out.println(decodedtext); // This correctly shows "kyle boon"
    }

    public byte[] encrypt(String message) throws Exception {
        final MessageDigest md = MessageDigest.getInstance("md5");
        final byte[] digestOfPassword = md.digest("HG58YZ3CR9"
                .getBytes("utf-8"));
        final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
        for (int j = 0, k = 16; j < 8;) {
            keyBytes[k++] = keyBytes[j++];
        }

        final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
        final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
        final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key, iv);

        final byte[] plainTextBytes = message.getBytes("utf-8");
        final byte[] cipherText = cipher.doFinal(plainTextBytes);
        // final String encodedCipherText = new sun.misc.BASE64Encoder()
        // .encode(cipherText);

        return cipherText;
    }

    public String decrypt(byte[] message) throws Exception {
        final MessageDigest md = MessageDigest.getInstance("md5");
        final byte[] digestOfPassword = md.digest("HG58YZ3CR9"
                .getBytes("utf-8"));
        final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24);
        for (int j = 0, k = 16; j < 8;) {
            keyBytes[k++] = keyBytes[j++];
        }

        final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
        final IvParameterSpec iv = new IvParameterSpec(new byte[8]);
        final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
        decipher.init(Cipher.DECRYPT_MODE, key, iv);

        // final byte[] encData = new
        // sun.misc.BASE64Decoder().decodeBuffer(message);
        final byte[] plainText = decipher.doFinal(message);

        return new String(plainText, "UTF-8");
    }
}

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此代码的问题在于它使用静态零字节 IV。最好为每个加密生成一个随机 IV 并将其存储在密文的前面。它不一定是秘密的，但它必须是不可预测的。 (3认同)
@AdrianHope-Bailie 这个建议是错误的，因为 MD5 仅输出 16 个字节，因此其余部分将用零填充。仅仅零永远不会成为一个好的密钥。 (2认同)

Answer 2

one*_*ros 17

这是一个使用javax.crypto库和apache commons编解码器库在Base64中进行编码和解码的解决方案:

import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import org.apache.commons.codec.binary.Base64;

public class TrippleDes {

    private static final String UNICODE_FORMAT = "UTF8";
    public static final String DESEDE_ENCRYPTION_SCHEME = "DESede";
    private KeySpec ks;
    private SecretKeyFactory skf;
    private Cipher cipher;
    byte[] arrayBytes;
    private String myEncryptionKey;
    private String myEncryptionScheme;
    SecretKey key;

    public TrippleDes() throws Exception {
        myEncryptionKey = "ThisIsSpartaThisIsSparta";
        myEncryptionScheme = DESEDE_ENCRYPTION_SCHEME;
        arrayBytes = myEncryptionKey.getBytes(UNICODE_FORMAT);
        ks = new DESedeKeySpec(arrayBytes);
        skf = SecretKeyFactory.getInstance(myEncryptionScheme);
        cipher = Cipher.getInstance(myEncryptionScheme);
        key = skf.generateSecret(ks);
    }


    public String encrypt(String unencryptedString) {
        String encryptedString = null;
        try {
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byte[] plainText = unencryptedString.getBytes(UNICODE_FORMAT);
            byte[] encryptedText = cipher.doFinal(plainText);
            encryptedString = new String(Base64.encodeBase64(encryptedText));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return encryptedString;
    }


    public String decrypt(String encryptedString) {
        String decryptedText=null;
        try {
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] encryptedText = Base64.decodeBase64(encryptedString);
            byte[] plainText = cipher.doFinal(encryptedText);
            decryptedText= new String(plainText);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return decryptedText;
    }


    public static void main(String args []) throws Exception
    {
        TrippleDes td= new TrippleDes();

        String target="imparator";
        String encrypted=td.encrypt(target);
        String decrypted=td.decrypt(encrypted);

        System.out.println("String To Encrypt: "+ target);
        System.out.println("Encrypted String:" + encrypted);
        System.out.println("Decrypted String:" + decrypted);

    }

}

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使用以下输出运行上述程序结果:

String To Encrypt: imparator
Encrypted String:FdBNaYWfjpWN9eYghMpbRA==
Decrypted String:imparator

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Answer 3

jlm*_*oca 11

我很难自己搞清楚,这篇文章帮助我找到了适合我案例的正确答案.当使用金融消息传递作为ISO-8583时,3DES要求非常具体,因此对于我的特殊情况,"DESede/CBC/PKCS5Padding"组合并未解决问题.在针对为金融界设计的一些3DES计算器对我的结果进行一些比较测试后,我发现"DESede/ECB/Nopadding"的值更适合于特定任务.

这是我的TripleDes类的演示实现(使用Bouncy Castle提供程序)



    import java.security.InvalidKeyException;
    import java.security.NoSuchAlgorithmException;
    import java.security.NoSuchProviderException;
    import java.security.Security;
    import javax.crypto.BadPaddingException;
    import javax.crypto.Cipher;
    import javax.crypto.IllegalBlockSizeException;
    import javax.crypto.NoSuchPaddingException;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.SecretKeySpec;
    import org.bouncycastle.jce.provider.BouncyCastleProvider;


    /**
     *
     * @author Jose Luis Montes de Oca
     */
    public class TripleDesCipher {
       private static String TRIPLE_DES_TRANSFORMATION = "DESede/ECB/Nopadding";
       private static String ALGORITHM = "DESede";
       private static String BOUNCY_CASTLE_PROVIDER = "BC";
       private Cipher encrypter;
       private Cipher decrypter;

       public TripleDesCipher(byte[] key) throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException,
             InvalidKeyException {
          Security.addProvider(new BouncyCastleProvider());
          SecretKey keySpec = new SecretKeySpec(key, ALGORITHM);
          encrypter = Cipher.getInstance(TRIPLE_DES_TRANSFORMATION, BOUNCY_CASTLE_PROVIDER);
          encrypter.init(Cipher.ENCRYPT_MODE, keySpec);
          decrypter = Cipher.getInstance(TRIPLE_DES_TRANSFORMATION, BOUNCY_CASTLE_PROVIDER);
          decrypter.init(Cipher.DECRYPT_MODE, keySpec);
       }

       public byte[] encode(byte[] input) throws IllegalBlockSizeException, BadPaddingException {
          return encrypter.doFinal(input);
       }

       public byte[] decode(byte[] input) throws IllegalBlockSizeException, BadPaddingException {
          return decrypter.doFinal(input);
       }
    }

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仅仅提供任何 3DES 代码似乎并不能解决我的问题。此外，在我看来，明确使用 ECB 和 NoPadding，以及在不需要的地方使用 BC 不符合这个答案。 (2认同)

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