“要解密的数据长度无效。”在Rijndael解密期间例外

I get "Length of the data to decrypt is invalid." exception when i try to decrypt a memory stream. I am beginner, cant figure out whats wrong. whats wrong?

我得到“要解密的数据长度无效”。当我尝试解密内存流时出现异常。我是初学者,不知道什么是错的。怎么了?

public bool EncryptStream()
    {

        string password = @"myKey123"; // Your Key Here
        UnicodeEncoding UE = new UnicodeEncoding();
        byte[] key = UE.GetBytes(password);

        s_EncryptedStream = new MemoryStream();
        int NoOfBytes;
        byte[] b_Buffer = new byte[8192];

        s_MemoryStream.Seek(0, SeekOrigin.Begin);

        RijndaelManaged RMCrypto = new RijndaelManaged();

        s_CrytpoStream = new CryptoStream(s_EncryptedStream,
            RMCrypto.CreateEncryptor(key, key),
            CryptoStreamMode.Write);

        while (s_MemoryStream.Length < s_MemoryStream.Position)
        {
            NoOfBytes = s_MemoryStream.Read(b_Buffer, 0, 8192);
            s_CrytpoStream.Write(b_Buffer, 0, NoOfBytes);
        }

        s_MemoryStream.Seek(0, SeekOrigin.Begin);

        while (s_EncryptedStream.Position < s_EncryptedStream.Length)
        {
            NoOfBytes = s_EncryptedStream.Read(b_Buffer, 0, 8192);
            s_MemoryStream.Write(b_Buffer, 0, NoOfBytes);

        }
        s_CrytpoStream.Flush();
        s_CrytpoStream.Close();

        return true;

    }


    public bool DecryptStream()
    {


        string password = @"myKey123"; // Your Key Here

        UnicodeEncoding UE = new UnicodeEncoding();
        byte[] key = UE.GetBytes(password);

        int NoOfBytes;
        byte[] b_Buffer = new byte[8192];

        s_DecryptedStream = new MemoryStream();


        RijndaelManaged RMCrypto = new RijndaelManaged();

        s_CrytpoStream = new CryptoStream(s_MemoryStream,
            RMCrypto.CreateDecryptor(key, key),
            CryptoStreamMode.Read);

        s_MemoryStream.Seek(0, SeekOrigin.Begin);

        while (s_MemoryStream.Length > s_MemoryStream.Position)
        {
            NoOfBytes = s_CrytpoStream.Read(b_Buffer, 0, 8192);
            s_DecryptedStream.Write(b_Buffer, 0, NoOfBytes);
        }

        s_DecryptedStream.Seek(0, SeekOrigin.Begin);
        s_MemoryStream.Seek(0, SeekOrigin.Begin);

        while (s_DecryptedStream.Position < s_DecryptedStream.Length)
        {
            NoOfBytes = s_DecryptedStream.Read(b_Buffer, 0, 8192);
            s_MemoryStream.Write(b_Buffer, 0, NoOfBytes);

        }

        s_CrytpoStream.Flush();
        s_CrytpoStream.Close();

        return true;

    }

3 个解决方案

#1

For a start, this while loop condition is never right:

首先,这个while循环条件永远不对:

while (s_MemoryStream.Length < s_MemoryStream.Position)

How can the position be beyond the length?

这个位置如何超越长度?

Rather than using the length of a stream, the usual pattern to copy a stream is to read repeatedly until the value returned isn't positive. As you're doing that twice in this code anyway, you might as well encapsulate it:

不是使用流的长度,而是复制流的通常模式是重复读取,直到返回的值不为正。正如你在这段代码中两次这样做的那样,你不妨把它封装起来:

public static void CopyStream(Stream input, Stream output)
{
    byte[] buffer = new byte[8192];
    int read;
    while ( (read = input.Read(buffer, 0, buffer.Length)) > 0)
    {
        output.Write(buffer, 0, read);
    }
}

It's also best to use using statements to clean up strings. Additionally, the Encoding.Unicode property means you don't have to create a new UnicodeEncoding yourself. Also, I generally find that setting the Position property is more readable than using Seek. Finally, there's no point in a method returning a value if it's always going to be true. So, your code would become:

最好使用using语句来清理字符串。此外,Encoding.Unicode属性意味着您不必自己创建新的UnicodeEncoding。另外,我通常发现设置Position属性比使用Seek更具可读性。最后,如果一个方法总是变为真,那么返回一个值是没有意义的。所以,你的代码将成为:

public void EncryptStream()
{
    string password = @"myKey123"; // Your Key Here
    byte[] key = Encoding.Unicode.GetBytes(password);

    s_EncryptedStream = new MemoryStream();
    s_MemoryStream.Position = 0;

    RijndaelManaged RMCrypto = new RijndaelManaged();

    using (Stream crytpoStream = new CryptoStream(s_EncryptedStream,
        RMCrypto.CreateEncryptor(key, key),
        CryptoStreamMode.Write))
    {
        CopyStream(s_MemoryStream, cryptoStream);
    }

    s_MemoryStream.Position = 0;
    s_EncryptedStream.Position = 0;
    CopyStream(s_EncryptedStream, s_MemoryStream);
}

public void DecryptStream()
{
    string password = @"myKey123"; // Your Key Here
    byte[] key = Encoding.Unicode.GetBytes(password);

    s_DecryptedStream = new MemoryStream();
    s_MemoryStream.Position = 0;

    RijndaelManaged RMCrypto = new RijndaelManaged();

    using (Stream crytpoStream = new CryptoStream(s_MemoryStream,
        RMCrypto.CreateDecryptor(key, key),
        CryptoStreamMode.Read))
    {
        CopyStream(cryptoStream, s_DecryptedStream);
    }

    s_DecryptedStream.Position = 0;
    s_MemoryStream.Position = 0;

    CopyStream(s_DecryptedStream, s_MemoryStream);
}

Even after amending this code, it feels like you've got way too many non-local variables here. I can't see why any of this should be in instance variables. Make the stream to be encrypted or decrypted a parameter (along with the password) and return a memory stream with the encrypted/decrypted data in, or just a byte array.

即使在修改了这段代码之后,感觉就像你在这里有太多的非局部变量。我不明白为什么这个应该在实例变量中。使流加密或解密为参数(连同密码)并返回带有加密/解密数据的内存流,或仅返回字节数组。

#2

You may need to call the FlushFinalBlock method on the CryptoStream after you have finished reading the input data. (ie. crytpoStream.FlushFinalBlock() after CopyStream)

完成读取输入数据后,可能需要在CryptoStream上调用FlushFinalBlock方法。 (即CopyStream之后的crytpoStream.FlushFinalBlock())

#3

I have come up with a solution and I have it posted on my new Blog

我已经提出了一个解决方案,并将其发布在我的新博客上

constotech.blogspot.com/2009/05/net-encryption-using-symmetricalgorithm.html

#1