Question

我尝试解密字节，但我在行length of data to decrypt is invalid read = cryptoStream.Read(buffer, 0, len);

中遇到错误“inputFile.lenght = 4256, len = 4256”

这是解密的代码

        byte[] salt = new byte[32];

        FileStream fsCrypt = new FileStream(inputFile, FileMode.Open);

        fsCrypt.Seek(fsCrypt.Length - 376, SeekOrigin.Begin);
        fsCrypt.Read(salt, 0, salt.Length);
        byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
        RijndaelManaged AES = new RijndaelManaged();
        AES.KeySize = 256;
        AES.BlockSize = 128;
        var key = new Rfc2898DeriveBytes(passwordBytes, salt, 50000);
        AES.Key = key.GetBytes(AES.KeySize / 8);
        AES.IV = key.GetBytes(AES.BlockSize / 8);
        AES.Padding = PaddingMode.PKCS7;
        AES.Mode = CipherMode.CFB;
        int read;
        byte[] buffer = new byte[1048576];
        List < byte > bytes = new List < byte > ();

        fsCrypt.Seek(0, SeekOrigin.Begin);
        read = 1;
        var len = Convert.ToInt32(fsCrypt.Length);

        MemoryStream mem = new MemoryStream();
        fsCrypt.CopyTo(mem);
        mem.Position = 0;
        using(CryptoStream cryptoStream = new CryptoStream(mem, AES.CreateDecryptor(), CryptoStreamMode.Read)) // CryptoStream cryptoStream = new CryptoStream(fsCrypt, AES.CreateDecryptor(), CryptoStreamMode.Read
         {
          //var buffer2 = new byte[len];
          while ((read = cs.Read(buffer, 0, buffer.Length)) > 0) {
           foreach(var m in buffer)
           bytes.Add(m);
          }
         }

你帮我吗？这段代码有什么问题？

我举了AES encryption on large files

的例子

我如何加密：

byte[] salt = GenerateRandomSalt();


 //convert password string to byte arrray
 byte[] passwordBytes = System.Text.Encoding.UTF8.GetBytes(password);

 //Set Rijndael symmetric encryption algorithm 71 246
 RijndaelManaged AES = new RijndaelManaged();
 AES.KeySize = 256;
 AES.BlockSize = 128;
 AES.Padding = PaddingMode.PKCS7;


 var key = new Rfc2898DeriveBytes(passwordBytes, salt, 50000);
 AES.Key = key.GetBytes(AES.KeySize / 8);
 AES.IV = key.GetBytes(AES.BlockSize / 8);

 AES.Mode = CipherMode.CFB;
 var kk = key.ToString();


 FileStream fsIn = new FileStream(inputFile, FileMode.Open);


 byte[] buffer = new byte[1048576];
 int read = 0;



 byte[] encrypted;
 using(MemoryStream msEncrypt = new MemoryStream()) {
  using(CryptoStream csEncrypt = new CryptoStream(msEncrypt, AES.CreateEncryptor(), CryptoStreamMode.Write)) {
   fsIn.Seek(0, SeekOrigin.Begin);

   while ((read = fsIn.Read(buffer, 0, buffer.Length)) > 0) {
    csEncrypt.Write(buffer, 0, read);
   }
   encrypted = msEncrypt.ToArray();
  }
 }

 fsIn.Seek(0, SeekOrigin.Begin);
 fsIn.Write(encrypted, 0, encrypted.Length);

 fsIn.Seek(fsIn.Length, SeekOrigin.Begin);
 fsIn.Write(salt, 0, salt.Length);

Answer 1

您在加密时过早地调用encrypted = msEncrypt.ToArray();，它必须在csEncrypt的using语句结束之后，因此所有数据都会被刷新到内存流中。

同样在您的解密中，您将开始在文件的早期

fsCrypt.Seek(fsCrypt.Length - 376, SeekOrigin.Begin);如果您的fsCrypt.Seek(fsCrypt.Length - 32, SeekOrigin.Begin);在写出时为salt.Length，则应该mem。

最后，在将盐传递给import UIKit import AVFoundation class QRScannerController: UIViewController, AVCaptureMetadataOutputObjectsDelegate { @IBOutlet weak var messageLabel: UILabel! static var isbn : String = "" var captureSession:AVCaptureSession? var videoPreviewLayer:AVCaptureVideoPreviewLayer? var qrCodeFrameView:UIView? let supportedCodeTypes = [AVMetadataObjectTypeEAN13Code] override func viewDidLoad() { super.viewDidLoad() // Get an instance of the AVCaptureDevice class to initialize a device object and provide the video as the media type parameter. let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo) do { // Get an instance of the AVCaptureDeviceInput class using the previous device object. let input = try AVCaptureDeviceInput(device: captureDevice) // Initialize the captureSession object. captureSession = AVCaptureSession() // Set the input device on the capture session. captureSession?.addInput(input) // Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session. let captureMetadataOutput = AVCaptureMetadataOutput() captureSession?.addOutput(captureMetadataOutput) // Set delegate and use the default dispatch queue to execute the call back captureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main) captureMetadataOutput.metadataObjectTypes = supportedCodeTypes // Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer. videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession) videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill videoPreviewLayer?.frame = view.layer.bounds view.layer.addSublayer(videoPreviewLayer!) // Start video capture. captureSession?.startRunning() // Move the message label and top bar to the front view.bringSubview(toFront: messageLabel) //view.bringSubview(toFront: topbar) // Initialize QR Code Frame to highlight the QR code qrCodeFrameView = UIView() if let qrCodeFrameView = qrCodeFrameView { qrCodeFrameView.layer.borderColor = UIColor.green.cgColor qrCodeFrameView.layer.borderWidth = 2 view.addSubview(qrCodeFrameView) view.bringSubview(toFront: qrCodeFrameView) } } catch { // If any error occurs, simply print it out and don't continue any more. print(error) return } } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } // MARK: - AVCaptureMetadataOutputObjectsDelegate Methods func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) { // Check if the metadataObjects array is not nil and it contains at least one object. if metadataObjects == nil || metadataObjects.count == 0 { qrCodeFrameView?.frame = CGRect.zero messageLabel.text = "No QR/barcode is detected" return } // Get the metadata object. let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject if supportedCodeTypes.contains(metadataObj.type) { // If the found metadata is equal to the QR code metadata then update the status label's text and set the bounds let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj) qrCodeFrameView?.frame = barCodeObject!.bounds if metadataObj.stringValue != nil { messageLabel.text = metadataObj.stringValue QRScannerController.isbn = metadataObj.stringValue print(QRScannerController.isbn) self.performSegue(withIdentifier: "showISBN", sender: self) } } }之前，您也不会将盐修剪掉，因此您将盐数据与密文一起传递到流中，这会使您的消息过长。

AES解密c＃

1 个答案: