StringCipher class

ElegantRecorder/ElegantOptions.cs

@@ -26,6 +26,8 @@ public class ElegantOptions
         public string ExePath { get; set; }
         [JsonIgnore]
         public string CurrRecName { get; set; }
+        [JsonIgnore]
+        public bool Encrypted { get; set; }
 
         public ElegantOptions()
         {
@@ -44,6 +46,7 @@ public ElegantOptions()
             FormHeight = 350;
             DataGridHeight = 155;
             CurrRecName = "";
+            Encrypted = false;
         }
 
         public void Save(string FilePath)

ElegantRecorder/Options.cs

@@ -36,6 +36,7 @@ public Options(ElegantRecorder elegantRecorder)
             buttonBrowseExe.Enabled = checkBoxRestrictToExe.Checked;
 
             comboBoxSpeed.SelectedItem = App.ElegantOptions.PlaybackSpeed;
+            checkBoxEncrypted.Checked = App.ElegantOptions.Encrypted;
             checkBoxRestrictToExe.Checked = App.ElegantOptions.RestrictToExe;
             textBoxExePath.Text = App.ElegantOptions.ExePath;
 
@@ -53,6 +54,7 @@ public void SaveOptions()
             App.ElegantOptions.StopHotkey = stopHotkeyData;
 
             App.ElegantOptions.PlaybackSpeed = comboBoxSpeed.SelectedItem as string;
+            App.ElegantOptions.Encrypted = checkBoxEncrypted.Checked;
             App.ElegantOptions.RestrictToExe = checkBoxRestrictToExe.Checked;
             App.ElegantOptions.ExePath = textBoxExePath.Text;
 

ElegantRecorder/Recording.cs

@@ -13,6 +13,7 @@ public class Recording
 
         public string Tag { get; set; }
         public string PlaybackSpeed { get; set; }
+        public bool Encrypted { get; set; }
         public bool RestrictToExe { get; set; }
         public string ExePath { get; set; }
         public UIAction[] UIActions { get; set; }
@@ -35,6 +36,7 @@ public Recording(ElegantRecorder app, string name)
             Tag = DefaultTag;
 
             PlaybackSpeed = "Normal";
+            Encrypted = false;
             RestrictToExe = false;
             ExePath = "";
 
@@ -49,13 +51,15 @@ private void SyncAppOptions(bool direction)
             if (direction)
             {
                 App.ElegantOptions.PlaybackSpeed = PlaybackSpeed;
+                App.ElegantOptions.Encrypted = Encrypted;
                 App.ElegantOptions.RestrictToExe = RestrictToExe;
                 App.ElegantOptions.ExePath = ExePath;
                 App.ElegantOptions.CurrRecName = Name;
             }
             else
             {
                 PlaybackSpeed = App.ElegantOptions.PlaybackSpeed;
+                Encrypted = App.ElegantOptions.Encrypted;
                 RestrictToExe = App.ElegantOptions.RestrictToExe;
                 ExePath = App.ElegantOptions.ExePath;
                 Name = App.ElegantOptions.CurrRecName;
@@ -111,6 +115,7 @@ public void Save()
 
                 stream.Write("\"Tag\":" + JsonSerializer.Serialize(DefaultTag) + ",");
                 stream.Write("\"PlaybackSpeed\":" + JsonSerializer.Serialize(PlaybackSpeed) + ",");
+                stream.Write("\"Encrypted\":" + JsonSerializer.Serialize(Encrypted) + ",");
                 stream.Write("\"RestrictToExe\":" + JsonSerializer.Serialize(RestrictToExe) + ",");
                 stream.Write("\"ExePath\":" + JsonSerializer.Serialize(ExePath) + ",");
 

ElegantRecorder/StringCipher.cs

@@ -0,0 +1,105 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace ElegantRecorder
+{
+    //source: https://stackoverflow.com/questions/69911084/problem-updating-to-net-6-encrypting-string
+    public static class StringCipher
+    {
+        // This constant is used to determine the keysize of the encryption algorithm in bits.
+        // We divide this by 8 within the code below to get the equivalent number of bytes.
+        private const int Keysize = 128;
+
+        // This constant determines the number of iterations for the password bytes generation function.
+        private const int DerivationIterations = 1000;
+
+        public static string Encrypt(string plainText, string passPhrase)
+        {
+            // Salt and IV is randomly generated each time, but is preprended to encrypted cipher text
+            // so that the same Salt and IV values can be used when decrypting.  
+            var saltStringBytes = Generate128BitsOfRandomEntropy();
+            var ivStringBytes = Generate128BitsOfRandomEntropy();
+            var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
+            using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
+            {
+                var keyBytes = password.GetBytes(Keysize / 8);
+                using (var symmetricKey = Aes.Create())
+                {
+                    symmetricKey.BlockSize = 128;
+                    symmetricKey.Mode = CipherMode.CBC;
+                    symmetricKey.Padding = PaddingMode.PKCS7;
+                    using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
+                    {
+                        using (var memoryStream = new MemoryStream())
+                        {
+                            using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
+                            {
+                                cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
+                                cryptoStream.FlushFinalBlock();
+                                // Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
+                                var cipherTextBytes = saltStringBytes;
+                                cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
+                                cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
+                                memoryStream.Close();
+                                cryptoStream.Close();
+                                return Convert.ToBase64String(cipherTextBytes);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        public static string Decrypt(string cipherText, string passPhrase)
+        {
+            // Get the complete stream of bytes that represent:
+            // [32 bytes of Salt] + [16 bytes of IV] + [n bytes of CipherText]
+            var cipherTextBytesWithSaltAndIv = Convert.FromBase64String(cipherText);
+            // Get the saltbytes by extracting the first 16 bytes from the supplied cipherText bytes.
+            var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
+            // Get the IV bytes by extracting the next 16 bytes from the supplied cipherText bytes.
+            var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
+            // Get the actual cipher text bytes by removing the first 64 bytes from the cipherText string.
+            var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();
+
+            using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
+            {
+                var keyBytes = password.GetBytes(Keysize / 8);
+                using (var symmetricKey = Aes.Create())
+                {
+                    symmetricKey.BlockSize = 128;
+                    symmetricKey.Mode = CipherMode.CBC;
+                    symmetricKey.Padding = PaddingMode.PKCS7;
+                    using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
+                    {
+                        using (var memoryStream = new MemoryStream(cipherTextBytes))
+                        {
+                            using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
+                            {
+                                var plainTextBytes = new byte[cipherTextBytes.Length];
+                                var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
+                                memoryStream.Close();
+                                cryptoStream.Close();
+                                return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        private static byte[] Generate128BitsOfRandomEntropy()
+        {
+            var randomBytes = new byte[16]; // 16 Bytes will give us 128 bits.
+            using (var rngCsp = RandomNumberGenerator.Create())
+            {
+                // Fill the array with cryptographically secure random bytes.
+                rngCsp.GetBytes(randomBytes);
+            }
+            return randomBytes;
+        }
+    }
+}