对于 AES 256 位，在 Java 中加密并在 C# 中解密 [英] Encrypt in java and Decrypt in C# For AES 256 bit

问题描述

1.我有java函数，可以加密xml文件并返回加密的字符串.

1.I have java function which encrypt xml file and return encrypted String.

/// Java Class 
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;

public class Crypt {

    public static String key = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
    public static byte[] key_Array = Base64.decodeBase64(key);

    public static String encrypt(String strToEncrypt)
    {       
        try
        {   
            //Cipher _Cipher = Cipher.getInstance("AES");
            //Cipher _Cipher = Cipher.getInstance("AES/ECB/PKCS5PADDING");
            //Cipher _Cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");      

            Key SecretKey = new SecretKeySpec(key_Array, "AES");

            Cipher _Cipher = Cipher.getInstance("AES");     
            _Cipher.init(Cipher.ENCRYPT_MODE, SecretKey);       

            return Base64.encodeBase64String(_Cipher.doFinal(strToEncrypt.getBytes()));     
        }
        catch (Exception e)
        {
            System.out.println("[Exception]:"+e.getMessage());
        }
        return null;
    }

    public static void main(String[] args) {        
        StringBuilder sb = new StringBuilder();
        sb.append("xml file string ...");

        String EncryptedString = encrypt(sb.toString());        
        System.out.println("[EncryptedString]:"+EncryptedString);
    }
}

2.我有c#函数来解密由java函数加密的消息.

2.I have c# function which decrypt the message which is encrypted by java function.

/// C# Function
private static string Decrypt(string encryptedText)
{
    RijndaelManaged aesEncryption = new RijndaelManaged();            
    aesEncryption.BlockSize = 256;
    //aesEncryption.KeySize = 256;
    //aesEncryption.Mode = CipherMode.CBC;
    //aesEncryption.Padding = PaddingMode.PKCS7;

    string keyStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
    //string ivStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";        

    byte[] keyArr = Convert.FromBase64String(keyStr);
    //byte[] ivArr = Convert.FromBase64String(ivStr);

    aesEncryption.Key = keyArr;
    //aesEncryption.IV = ivArr;

    ICryptoTransform decrypto = aesEncryption.CreateDecryptor();

    byte[] encryptedBytes = Convert.FromBase64CharArray(encryptedText.ToCharArray(), 0, encryptedText.Length);  
    byte[] decryptedData = decrypto.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length); /// CryptographicException: Length of the data to decrypt is invalid.    
    return ASCIIEncoding.UTF8.GetString(decryptedData); 
}

Java 加密功能运行良好.但问题是 C# 函数，
当我解密时，我收到以下错误消息

Java encrypt function is work well. But the problem is C# function,
when I decrypt I get below error message

CryptographicException: Length of the data to decrypt is invalid.

我使用以下参考搜索了解决方案

I searched solutions by using below ref

1. Java 中的 AES 加密和 C# 中的解密
2. C#/Java |AES256 加密/解密
3. C# 和 Java 中的加密/解密

但我仍然面临同样的错误.谁能给我建议.

but I still face the same error.Could anyone give me suggestion please.

我只是更改了我的 C# 加密函数.以下是我的更改列表

I Just change my C# crypto function. Below is my change lists

1. 块大小为 128
2. 密钥大小为 256
3. IV 大小为 16
4. 密钥大小为 32

/// Updated decrypt function
private static string Decrypt(string encryptedText)
{
    RijndaelManaged aesEncryption = new RijndaelManaged();            
    aesEncryption.BlockSize = 128;
    aesEncryption.KeySize = 256;

    //aesEncryption.Mode = CipherMode.CBC;
    aesEncryption.Padding = PaddingMode.None;

    string keyStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
    string ivStr = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";           

    byte[] ivArr = Convert.FromBase64String(ivStr);
    byte[] IVkey16BytesValue = new byte[16];
    Array.Copy(ivArr, IVkey16BytesValue, 16);

    byte[] keyArr = Convert.FromBase64String(keyStr);
    byte[] KeyArr32BytesValue = new byte[32];
    Array.Copy(keyArr, KeyArr32BytesValue, 32);

    aesEncryption.IV = IVkey16BytesValue;
    aesEncryption.Key = KeyArr32BytesValue; 

    ICryptoTransform decrypto = aesEncryption.CreateDecryptor();

    byte[] encryptedBytes = Convert.FromBase64CharArray(encryptedText.ToCharArray(), 0, encryptedText.Length);
    byte[] decryptedData = decrypto.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length); 
    return ASCIIEncoding.UTF8.GetString(decryptedData);
}

此时，没有发生错误.但是我收到了无法阅读的解密消息.

In this time, no error occur. But I get decrypted message which i cannot read.

g:��	d��Y\符O����
L��W�wHm�>f�au����%��0�� ..........

请让我再次听取您的建议.

Please let me get your suggestion again.

推荐答案

我认为 blockSize 应该是 128，keysize 应该是 256.keyStr 应该是 32 个字符长，IVstr 应该是 16 个字符长.这可能会有所帮助，因为它描述了为什么必须使用 128 位作为块大小以及密钥大小可以是多少.csrc.nist.gov/publications/fips/fips197/fips-197.pdf

I believe the blockSize should be 128 and the keysize be 256. The keyStr should be 32 characters long and the IVstr should be 16 characters long. This may help as it describes why 128 bits have to be used for block size and what the key sizes can be. csrc.nist.gov/publications/fips/fips197/fips-197.pdf

你在解密方法中有这个.

You have this in the decrypt method.

    aesEncryption.Padding = PaddingMode.None; 

我相信你也需要把它放在加密方法中.

I believe you need to put that in the encrypt method also.

另外，为什么不将这种方法用于密钥和 IV.

Also why not use this method for the key and IV.

    aes.Key = ASCIIEncoding.ASCII.GetBytes(keyStr); 
    aes.IV = ASCIIEncoding.ASCII.GetBytes(ivStr);

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