Xamrin UWP 发布导致奇怪的 NullReferenceException (System.Security.Cryptography.PasswordDeriveBytes)

问题描述

public static class CryptoHelper {
    // This size of the IV (in bytes) must = (keysize / 8).  Default keysize is 256,so the IV must be
    // 32 bytes long.  Using a 16 character string here gives us 32 bytes when converted to a byte array.
    private const string initVector = "pemgail9uzpgzl88";
    // This constant is used to determine the keysize of the encryption algorithm
    private static int keysize = 256;

    private static int getKeySize()
    {
        return 256;
    }

    //Encrypt
    //public static byte[] EncryptString( string plainText,string passphrase ) {
    public static byte[] EncryptString(string toEncrypt,string salt)
    {
        byte[] initVectorBytes = Encoding.UTF8.GetBytes(initVector);
        byte[] plainTextBytes = Encoding.UTF8.GetBytes(toEncrypt);

        byte[] keyBytes = new byte[126];
        try
        {
            PasswordDeriveBytes password = new PasswordDeriveBytes(Encoding.UTF8.GetBytes(salt),null);

            Debug.WriteLine(CryptoHelper.getKeySize());
            Debug.WriteLine(password.ToString());
            keyBytes = password.GetBytes(256 / 8);
        } catch (Exception e)
        {
            Debug.WriteLine(e.StackTrace);
        }
        

        
        RijndaelManaged symmetricKey = new RijndaelManaged();
        symmetricKey.Mode = CipherMode.CBC;
        ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes,initVectorBytes);
        MemoryStream memoryStream = new MemoryStream();
        CryptoStream cryptoStream = new CryptoStream(memoryStream,encryptor,CryptoStreamMode.Write);
        cryptoStream.Write(plainTextBytes,plainTextBytes.Length);
        cryptoStream.FlushFinalBlock();
        byte[] cipherTextBytes = memoryStream.ToArray();
        memoryStream.Close();
        cryptoStream.Close();
        return cipherTextBytes;
    }
 ........

调用“password.GetBytes(256 / 8);”导致不可捕获的 NullReferenceException 这仅在 UWP 应用处于发布模式时发生； UWP Debug以及Andorid和IOS都可以。

我还收到一条奇怪的调试消息：

“this._hash”战争“空”。

或

"this._hash" 是 "null"。 （已翻译）

在这里你可以看到它在行动 VS2019 Screenshot

为了解决这个问题，函数的输入是：

toEncrypt “承载eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzUxMiJ9.eyJzdWIiOiIxIiwiZXhwIjoxNjE3MDAyMTEyfQ.C0CaGgfibM4z55MoANI2CiohUyew09r3_D_TpcQ6n1c8LmQd8BusSyF1SMEIQ3cO5uxE9Tnau0ZAT6D3kN3NcQ”

盐 "9x83m74tzrx9387x4mz98374zt90x8m273z948734z59"

因为我看不到此问题的详细原因，因此无法找到解决方法。

解决方法

我试图使相同的代码工作。我找到的解决方案是替换：

PasswordDeriveBytes password = new PasswordDeriveBytes(Encoding.UTF8.GetBytes(salt),null);

与：

 Rfc2898DeriveBytes password = new Rfc2898DeriveBytes(passPhrase,Encoding.UTF8.GetBytes("12345678"));

并添加：

symmetricKey.Padding = PaddingMode.Zeros;