Here are the steps:

Step 1:

Create a simple Windows Runtime Project. Click New Project, Visual C#, Windows 8, Windows, then Blank App (Windows 8.1).

Step 2:

Let's add two buttons in MainPage.xaml with click events:

  • Encrypt Button
  • Decrypt Button
  1. <Page
  2. x:Class="Encrypt_Decrypt.MainPage"
  3. xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  4. xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  5. xmlns:local="using:Encrypt_Decrypt"
  6. xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  7. xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  8. mc:Ignorable="d">
  10. <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
  11. <Button Content="Encrypt" Name="btn_Encrypt" Height="125" Margin="65,365,0,278" Width="225" Click="btn_Encrypt_Click"></Button>
  12. <Button Content="Decrypt" Name="btn_Decrypt" Margin="350,365,0,278" Height="125" Width="231" Click="btn_Decrypt_Click"></Button>
  13. </Grid>
  14. </Page>
Step 3:

Let's add a text file in Solution Explorer for testing purpose. We will copy that file from Installed Location to Local folder and encrypt it.



Step 4: Name it ‘OriginalFile.txt’


Step 5:Add some text in this text file.


Step 6:

In the code behind: MainPage.xaml.cs, Update your code with this:

  1. using System;
  2. using System.Collections.Generic;
  3. using System.Diagnostics;
  4. using System.IO;
  5. using System.Linq;
  6. using System.Runtime.InteropServices.WindowsRuntime;
  7. using Windows.ApplicationModel;
  8. using Windows.Foundation;
  9. using Windows.Foundation.Collections;
  10. using Windows.Storage;
  11. using Windows.Storage.Streams;
  12. using Windows.UI.Xaml;
  13. using Windows.UI.Xaml.Controls;
  14. using Windows.UI.Xaml.Controls.Primitives;
  15. using Windows.UI.Xaml.Data;
  16. using Windows.UI.Xaml.Input;
  17. using Windows.UI.Xaml.Media;
  18. using Windows.UI.Xaml.Navigation;
  21. namespace Encrypt_Decrypt
  22. {

  24. public sealed partial class MainPage : Page
  25. {
  26. public MainPage()
  27. {
  28. this.InitializeComponent();
  29. }
  31. private async void btn_Encrypt_Click(object sender, RoutedEventArgs e)
  32. {
  33. //For Copying File from Installed Location to Local Folder
  34. StorageFolder appFolder = ApplicationData.Current.LocalFolder;
  35. StorageFile stopfile = await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///OriginalFile.txt"));
  36. await stopfile.CopyAsync(ApplicationData.Current.LocalFolder, "OriginalFile.txt", NameCollisionOption.ReplaceExisting);
  38. string sourceFileName = "OriginalFile.txt";
  39. string destinationFileName = "EncryptedFile.txt";
  41. try
  42. {
  43. StorageFile file = await appFolder.GetFileAsync(sourceFileName);
  44. IBuffer fileStreamBuffer = await FileIO.ReadBufferAsync(file);
  45. string protectionDescriptor = "LOCAL=user";
  46. if (fileStreamBuffer.Length != 0)
  47. {
  48. Windows.Security.Cryptography.DataProtection.DataProtectionProvider provider = String.IsNullOrEmpty(protectionDescriptor) ? new Windows.Security.Cryptography.DataProtection.DataProtectionProvider() : new Windows.Security.Cryptography.DataProtection.DataProtectionProvider(protectionDescriptor);
  49. IBuffer encryptedBuffer = await provider.ProtectAsync(fileStreamBuffer);
  51. StorageFile encryptedFile = await appFolder.CreateFileAsync(destinationFileName, CreationCollisionOption.ReplaceExisting);
  52. await FileIO.WriteBufferAsync(encryptedFile, encryptedBuffer);
  53. }
  54. }
  55. catch (Exception ex)
  56. {
  57. Debug.WriteLine(ex.ToString());
  58. }
  59. }
  62. private async void btn_Decrypt_Click(object sender, RoutedEventArgs e)
  63. {
  64. StorageFolder appFolder = ApplicationData.Current.LocalFolder;
  65. string sourceFileName = "EncryptedFile.txt";
  66. string destinationFileName = "DecryptedFile.txt";
  67. try
  68. {
  69. StorageFile file = await appFolder.GetFileAsync(sourceFileName);
  70. IBuffer fileStreamBuffer = await FileIO.ReadBufferAsync(file);
  71. string protectionDescriptor = "LOCAL=user";
  72. if (fileStreamBuffer.Length != 0)
  73. {
  74. Windows.Security.Cryptography.DataProtection.DataProtectionProvider provider = String.IsNullOrEmpty(protectionDescriptor) ? new Windows.Security.Cryptography.DataProtection.DataProtectionProvider() : new Windows.Security.Cryptography.DataProtection.DataProtectionProvider(protectionDescriptor);
  75. IBuffer encryptedBuffer = await provider.UnprotectAsync(fileStreamBuffer);
  77. StorageFile encryptedFile = await appFolder.CreateFileAsync(destinationFileName, CreationCollisionOption.ReplaceExisting);
  78. await FileIO.WriteBufferAsync(encryptedFile, encryptedBuffer);
  79. }
  80. }
  81. catch (Exception ex)
  82. {
  83. Debug.WriteLine(ex.ToString());
  84. }
  85. }
  86. }
  87. }

Step 7:

Run the application. Click on Encrypt and Decrypt button. You can see the files being encrypted and decrypted in the Application Local Folder:

This PC, C, Users > [Your User Name] > AppData, Local, Packages > [App package name] > LocalState,


That’s it.

Thanks, Happy Coding!

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