解密後無法打開xml 1個字節到很多？

Question

我試圖加密XML，並解密後，我結束了1個字節太多 - 可能是因爲填充。這是我的代碼。我怎樣才能改變這個使它工作？

public byte[] encryptData(byte[] source,string key) 
{ 
    byte[] btKeyInBytes = UTF8Encoding.UTF8.GetBytes(key); 
    Rfc2898DeriveBytes rfc = new Rfc2898DeriveBytes(key, btKeyInBytes); 

    AesManaged encryptor = new AesManaged(); 
    encryptor.Padding = PaddingMode.Zeros; 

    using (MemoryStream encryptStream = new MemoryStream()) 
    { 
     using (CryptoStream encStream = new CryptoStream(encryptStream, encryptor.CreateEncryptor(rfc.GetBytes(16), rfc.GetBytes(16)), CryptoStreamMode.Read)) 
     { 
      //Read from the input stream, then encrypt and write to the output stream. 
      encStream.Write(source, 0, source.Length); 
      encStream.FlushFinalBlock(); 
      encryptor.Clear(); 
     } 
     encryptStream.Flush(); 
     encryptedSource = encryptStream.ToArray(); 
    } 
    return encryptedSource; 
} 

public byte[] decryptData(byte[] source, string key) 
{ 
    byte[] encryptedSource = null; 

    byte[] btKeyInBytes = UTF8Encoding.UTF8.GetBytes(key); 
    Rfc2898DeriveBytes rfc = new Rfc2898DeriveBytes(key, btKeyInBytes); 

    AesManaged encryptor = new AesManaged(); 
    encryptor.Padding = PaddingMode.Zeros; 

    using (MemoryStream encryptStream = new MemoryStream()) 
    { 
     using (CryptoStream encStream = new CryptoStream(encryptStream, encryptor.CreateDecryptor(rfc.GetBytes(16), rfc.GetBytes(16)), CryptoStreamMode.Write)) 
     { 
      //Read from the input stream, then encrypt and write to the output stream. 
      encStream.Write(source, 0, source.Length); 
      encStream.FlushFinalBlock(); 
      encryptor.Clear(); 
     } 
     encryptStream.Flush(); 
     encryptedSource = encryptStream.ToArray(); 
    } 

    return encryptedSource; 
} 

看來，填充給我解密

Answer 1

我明白了！

現在讓我們試着解釋。

比方說，我有一個927字節的文件。

我所做的就是讀取這個文件並將其分成656個字節。這個656字節的字節數組正在被加密。第二個數組將是271個字節。

在每個加密塊中，我都使用了padding。解密時，您將無法知道使用哪個塊填充，因爲每個塊現在可以被16除（因爲加密填充）。基本上我只想要填充用於最後一個塊（271）。

，所以這是我的新代碼：

public byte[] encryptData(byte[] source, string key, bool padding) 
{ 
    byte[] encryptedSource = null; 


    byte[] btKeyInBytes = UTF8Encoding.UTF8.GetBytes(key); 
    Rfc2898DeriveBytes rfc = new Rfc2898DeriveBytes(key, btKeyInBytes); 

    AesManaged encryptor = new AesManaged(); 
    //encryptor.Mode = CipherMode.CFB; 
    encryptor.KeySize = 128;   // in bits  
    encryptor.Key = new byte[128/8]; // 16 bytes for 128 bit encryption  
    encryptor.IV = new byte[128/8]; 
    if (padding) { encryptor.Padding = PaddingMode.PKCS7; } 
    else { encryptor.Padding = PaddingMode.None; } 


    using (MemoryStream encryptStream = new MemoryStream()) 
    { 
     using (CryptoStream encStream = 
        new CryptoStream(encryptStream, 
            encryptor.CreateEncryptor(rfc.GetBytes(16), 
                   rfc.GetBytes(16)), 
            CryptoStreamMode.Write)) 
     { 
      //Read from the input stream, then encrypt and write to the output stream. 
      encStream.Write(source, 0, source.Length); 
     } 
     encryptStream.Flush(); 
     encryptedSource = encryptStream.ToArray(); 
    } 
    return encryptedSource; 
} 

public byte[] decryptData(byte[] source, string key,bool padding) 
{ 
    byte[] encryptedSource = null; 

    byte[] btKeyInBytes = UTF8Encoding.UTF8.GetBytes(key); 
    Rfc2898DeriveBytes rfc = new Rfc2898DeriveBytes(key, btKeyInBytes); 

    AesManaged encryptor = new AesManaged(); 
    encryptor.Key = new byte[128/8]; // 16 bytes for 128 bit encryption  
    encryptor.IV = new byte[128/8]; 
    if (padding) { encryptor.Padding = PaddingMode.PKCS7; } 
    else { encryptor.Padding = PaddingMode.None; } 


    using (MemoryStream encryptStream = new MemoryStream()) 
    { 
     using (CryptoStream encStream = 
       new CryptoStream(encryptStream, 
            encryptor.CreateDecryptor(rfc.GetBytes(16), 
                  rfc.GetBytes(16)), 
            CryptoStreamMode.Write)) 
     { 
      //Read from the input stream, then encrypt and write to the output stream. 
      encStream.Write(source, 0, source.Length); 
     } 
     encryptStream.Flush(); 
     encryptedSource = encryptStream.ToArray(); 

    } 

    return encryptedSource; 
} 

我希望這有助於！

Answer 2

在1個額外的字節。如果你的問題是填充，然後PaddingMode.Zeros是關於最糟糕的選擇，因爲零不能總是被可靠地去除。最好使用PKCS7填充。

系統之間的行尾編碼也可能發生改變。有些系統使用一個字節，而其他系統使用兩個字節。正如@Rup所建議的，您真的需要逐字節地查看解密文件中的內容。