Question

我想解密一个长字节[]，但是我无法做到这一点。

接收代码：我直接从流中读取bitmap（按预期方式工作），然后使用byte[]将其转换为MemoryStream，然后解密整个byte[]，然后解密的数据应该变成bitmap：

Bitmap bmpTmp = BitmapFactory.DecodeStream(CommunicationHandler.GetStream());
MemoryStream stream = new MemoryStream();
bmpTmp.Compress(Bitmap.CompressFormat.Png, 100, stream);
string imageString = DecryptStringFromBytes_Aes(stream.ToArray());

顺便说一句，我将流读入bitmap然后将其转换为byte[]而不是将流读入byte[]的唯一原因是找不到任何将NetworkStream读入byte[]的函数。我想知道BitmapFactory.DecodeStream()是如何工作的？该功能如何读取全部数据？它怎么知道什么时候停止？

解密代码：

public static string DecryptStringFromBytes_Aes(byte[] cipherTextCombined)
    {
        string plaintext = null;

        // Create an Aes object with the specified key and IV.
        using (Aes aesAlg = Aes.Create())
            {
                aesAlg.Key = key;
                aesAlg.Padding = PaddingMode.Zeros;
                aesAlg.Mode = CipherMode.CBC;

                byte[] IV = new byte[16];
                byte[] cipherText = new byte[cipherTextCombined.Length - IV.Length];

                Array.Copy(cipherTextCombined, IV, IV.Length);
                Array.Copy(cipherTextCombined, IV.Length, cipherText, 0, cipherText.Length);

                aesAlg.IV = IV;

                // Create a decryptor to perform the stream transform.
                ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

                // Create the streams used for decryption.
                using (MemoryStream msDecrypt = new MemoryStream(cipherText))
                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                            plaintext = srDecrypt.ReadToEnd(); //The error occurs here: 
//System.ArgumentException: Offset and length were out of bounds for the array or count is 
//greater than the number of elements from index to the end of the source collection. 
            }

        return plaintext.TrimEnd('\0');
    }

加密代码：

def encrypt(self, message):
    message = self.pad(message)
    iv = Random.new().read(AES.block_size)
    cipher = AES.new(str.encode(self.key), AES.MODE_CBC, iv)
    return iv + cipher.encrypt(message)

填充代码：

def pad(s): 
    return s + b"\0" * (AES.block_size - len(s) % AES.block_size)

这是我通过NetworkStream发送的内容：

import mss.tools

def screenshot():
    with mss.mss() as sct:
        return sct.grab(sct.monitors[1])

socket.send(mss.tools.to_png(image.rgb, image.size))

根据我得到的错误-System.ArgumentException: Offset and length were out of bounds for the array or count is greater than the number of elements from index to the end of the source collection.，我认为输入太长。这是错误堆栈跟踪：at Project.LoadingImage.RunInBackground (Java.Lang.Void[] params) [0x0004d]。

请注意，方法和系统在简单和简短的输入下都能完美地工作，但是唯一的问题是图像，可能是由于错误提示，byte[]输入太大了。

此外，请注意，解密方法返回string而不返回byte[]，这使得将其解码为bitmap更加复杂。

最后，有3个主要问题：

错误是什么意思？我该如何解决？
BitmapFactory.DecodeStream()如何读取整个流？
是否可以将解密函数的返回类型从byte[]更改为string？

解密长字节数组

0 个答案: