Java 中的 AES 加密和 C# 中的解密

问题描述

您好，我已经加密了使用标准 AES 算法加密的十六进制字符串和密钥.代码:

Hello I've Encrypted Hex string and Key that has been encrypted using standard AES Algorithm.Code:

        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:

Now I try to decrypt it using C#Code:

            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.请指出我哪里出错了?

but the output is not as expected.Please point out where I'm going wrong?

推荐答案

你的代码有一个大问题:它混合了字符编码！

Your code has one big problem: It is mixing the character encodings!

在 Java 中，您调用 key.getBytes()，不带参数.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.

In Java you are calling key.getBytes(), without arguments. This method returns the UTF-8 or CP1252/ISO 8859-1 encoded data depending on your operating system and the default charset in Java.

在 C# 方面，您使用 Encoding.Unicode.GetBytes(key) - "Unicode" in .Net 是双字节字符别名 UTF-16 (Little-Endian) 的同义词.因此，您在 C# 中使用了不同的键.

On C# side you are using Encoding.Unicode.GetBytes(key) - "Unicode" in .Net is a synonym for double byte characters alias UTF-16 (Little-Endian). Therefore you are using a different key in C#.

通过比较 Java 和 C# 中的字节数，您应该能够看到差异:

You should be able to see the difference by comparing the number of bytes in Java and C#:

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.

I strongly recommend you to use byte arrays instead of Strings for defining a cryptographic key.

更新:另一个区别是您在 C# 中设置了一个初始化向量 (IV)，而在 Java 中则没有.当您使用 ECB 时，不应使用 IV，但如果您更改为 CBC，例如这会产生很大的不同.

Update: Another difference is that you are setting an initialization vector (IV) in C# which you don't do in Java. As you are using ECB the IV should not be used but if you change to CBC for example this makes a big difference.

这篇关于Java 中的 AES 加密和 C# 中的解密的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！