Question

您好我已使用标准AES算法加密的加密十六进制字符串和密钥。代码：

        final String key = "=abcd!#Axd*G!pxP";
        final javax.crypto.spec.SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), "AES");
        final javax.crypto.Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, keySpec);
        byte [] encryptedValue = cipher.doFinal(input.getBytes());
        return new String(org.apache.commons.codec.binary.Hex.encodeHex(encryptedValue));

现在我尝试使用C＃解密它代码：

            RijndaelManaged rijndaelCipher = new RijndaelManaged();
            // Assumed Mode and padding values.
            rijndaelCipher.Mode = CipherMode.ECB;
            rijndaelCipher.Padding = PaddingMode.None;

            // AssumedKeySize and BlockSize values.
            rijndaelCipher.KeySize = 0x80;
            rijndaelCipher.BlockSize = 0x80;
            // Convert Hex keys to byte Array.
            byte[] encryptedData = hexStringToByteArray(textToDecrypt);

            byte[] pwdBytes = Encoding.Unicode.GetBytes(key);
            byte[] keyBytes = new byte[0x10];
            int len = pwdBytes.Length;
            if (len > keyBytes.Length)
            {
                len = keyBytes.Length;
            }
            Array.Copy(pwdBytes, keyBytes, len);
            rijndaelCipher.Key = keyBytes;
            rijndaelCipher.IV = keyBytes;
            // Decrypt data
            byte[] plainText = rijndaelCipher.CreateDecryptor().TransformFinalBlock(encryptedData, 0, encryptedData.Length);
            str = Encoding.UTF8.GetString(plainText);

和

    static private byte[] HexToBytes(string str)
    {
        if (str.Length == 0 || str.Length % 2 != 0)
            return new byte[0];
        byte[] buffer = new byte[str.Length / 2];
        char c;
        for (int bx = 0, sx = 0; bx < buffer.Length; ++bx, ++sx)
        {
            // Convert first half of byte   
            c = str[sx];
            buffer[bx] = (byte)((c > '9' ? (c > 'Z' ? (c - 'a' + 10) : (c - 'A' + 10)) : (c - '0')) << 4);
            // Convert second half of byte    
            c = str[++sx];
            buffer[bx] |= (byte)(c > '9' ? (c > 'Z' ? (c - 'a' + 10) : (c - 'A' + 10)) : (c - '0'));
        }
        return buffer;
    }

但输出不符合预期。请指出我出错的地方？

Answer 1

你的代码有一个大问题：它混合了字符编码！

在Java中，您调用key.getBytes()，没有参数。此方法返回UTF-8或CP1252 / ISO 8859-1编码数据，具体取决于您的操作系统和Java中的默认字符集。

在C＃端，您使用的是Encoding.Unicode.GetBytes(key) - "Unicode" in .Net is a synonym for double byte characters alias UTF-16 (Little-Endian)。因此，您在C＃中使用了不同的密钥。

您应该能够通过比较Java和C＃中的字节数来看到差异：

Java："=abcd!#Axd*G!pxP".getBytes().length = 16

C＃：Encoding.Unicode.GetBytes("=abcd!#Axd*G!pxP").Length = 32

我强烈建议您使用字节数组而不是字符串来定义加密密钥。

更新：另一个不同之处在于您在C＃中设置初始化向量（IV），而在Java中则没有这样做。当您使用ECB时，不应使用IV，但如果您更改为CBC，则会产生很大的不同。

Answer 2

我不仅需要C＃，还需要兼容Silverlight和Windows Phone 7。而且我完全厌倦了缺乏Java和C＃（以及基于Base64）可接受的完整示例。

代码不是什么花哨的东西，但有效。请随意改进，因为我将其标记为社区维基，但请务必在提交任何更改之前对其进行测试。

这是C＃代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;
//Author: Doguhan Uluca
//Website: www.deceivingarts.com

namespace DeceivingArts.Common
{
    public class Encryptor
    {
        private string _seed = "";

        public Encryptor(string seed)
        {
        _seed = seed;
        }

        public string Encrypt<TSymmetricAlgorithm>(string input) where TSymmetricAlgorithm : SymmetricAlgorithm, new()
        {
            var pwdBytes = Encoding.UTF8.GetBytes(_seed);
            using(TSymmetricAlgorithm sa = new TSymmetricAlgorithm())
            {
                ICryptoTransform saEnc = sa.CreateEncryptor(pwdBytes, pwdBytes);

                var encBytes = Encoding.UTF8.GetBytes(input);

                var resultBytes = saEnc.TransformFinalBlock(encBytes, 0, encBytes.Length);

                return Convert.ToBase64String(resultBytes);
            }
        }

        public string Decrypt<TSymmetricAlgorithm>(string input) where TSymmetricAlgorithm : SymmetricAlgorithm, new()
        {
            var pwdBytes = Encoding.UTF8.GetBytes(_seed);
            using(TSymmetricAlgorithm sa = new TSymmetricAlgorithm())
            {
                ICryptoTransform saDec = sa.CreateDecryptor(pwdBytes, pwdBytes);

                var encBytes = Convert.FromBase64String(input);

                var resultBytes = saDec.TransformFinalBlock(encBytes, 0, encBytes.Length);
                return Encoding.UTF8.GetString(resultBytes);
            }
        }
    }
}

这是Android兼容的Java代码：

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

/**
 * Usage:
 * <pre>
 * String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)
 * ...
 * String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)
 * </pre>
 * @author ferenc.hechler
 * @author Doguhan Uluca
 */
public class Encryptor {

    public static String encrypt(String seed, String cleartext) throws Exception {
            byte[] rawKey = getRawKey(seed.getBytes());
            byte[] result = encrypt(rawKey, cleartext.getBytes());
            return toBase64(result);
    }

    public static String decrypt(String seed, String encrypted) throws Exception {
            byte[] rawKey = getRawKey(seed.getBytes());
            byte[] enc = fromBase64(encrypted);
            byte[] result = decrypt(rawKey, enc);
            return new String(result);
    }

    private static byte[] getRawKey(byte[] seed) throws Exception {
        SecretKey skey = new SecretKeySpec(seed, "AES");

        byte[] raw = skey.getEncoded();

        return raw;
    }

    private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        IvParameterSpec ivParameterSpec = new IvParameterSpec(raw);

        cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivParameterSpec);
        byte[] encrypted = cipher.doFinal(clear);
        return encrypted;
    }

    private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        IvParameterSpec ivParameterSpec = new IvParameterSpec(raw);

        cipher.init(Cipher.DECRYPT_MODE, skeySpec, ivParameterSpec);
        byte[] decrypted = cipher.doFinal(encrypted);
        return decrypted;
    }

    public static String toBase64(byte[] buf)
    {
        return Base64.encodeBytes(buf);
    }

    public static byte[] fromBase64(String str) throws Exception
    {
        return Base64.decode(str);
    }
}

对于Base64转换，请参阅http://iharder.net/base64的优秀实施。

我希望这可以节省人们的时间。

Answer 3

试试这个组合：

aesAlg.Mode = CipherMode.ECB;   
aesAlg.Padding = PaddingMode.PKCS7;   
//aesAlg.IV; - use default (not assign)

Answer 4

我怀疑错误是你没有在这个等式的Java方面指定填充或操作模式。我不确定Java的AES实现默认是什么，但我会从获取密码时开始指定两者。例如：

Cipher.getInstance("<algorithm>/<mode of operation>/<padding>");

您需要在Java中查找AES支持的填充方案和操作模式，然后确保将C＃代码配置为使用完全相同的配置。

Java中的AES加密和C＃中的解密

4 个答案: