Created a key derivation interface and initial Pkcs5 implementation

mRemoteV1/Security/KeyDerivation/IKeyDerivationFunction.cs

@@ -0,0 +1,8 @@
+
+namespace mRemoteNG.Security.KeyDerivation
+{
+    public interface IKeyDerivationFunction
+    {
+        byte[] DeriveKey(string password, byte[] salt);
+    }
+}

mRemoteV1/Security/KeyDerivation/Pkcs5S2KeyGenerator.cs

@@ -0,0 +1,31 @@
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Generators;
+using Org.BouncyCastle.Crypto.Parameters;
+
+
+namespace mRemoteNG.Security.KeyDerivation
+{
+    public class Pkcs5S2KeyGenerator : IKeyDerivationFunction
+    {
+        private readonly int _iterations;
+        private readonly int _keyBitSize;
+
+        public Pkcs5S2KeyGenerator(int keyBitSize = 256, int iterations = 1000)
+        {
+            _keyBitSize = keyBitSize;
+            _iterations = iterations;
+        }
+
+        public byte[] DeriveKey(string password, byte[] salt)
+        {
+            var passwordInBytes = PbeParametersGenerator.Pkcs5PasswordToBytes(password.ToCharArray());
+
+            var keyGenerator = new Pkcs5S2ParametersGenerator();
+            keyGenerator.Init(passwordInBytes, salt, _iterations);
+
+            var keyParameter = (KeyParameter) keyGenerator.GenerateDerivedMacParameters(_keyBitSize);
+            var keyBytes = keyParameter.GetKey();
+            return keyBytes;
+        }
+    }
+}

mRemoteV1/mRemoteV1.csproj

@@ -192,6 +192,8 @@
     <Compile Include="Security\EncryptedSecureString.cs" />
     <Compile Include="Security\Authentication\IAuthenticator.cs" />
     <Compile Include="Security\EncryptionException.cs" />
+    <Compile Include="Security\KeyDerivation\IKeyDerivationFunction.cs" />
+    <Compile Include="Security\KeyDerivation\Pkcs5S2KeyGenerator.cs" />
     <Compile Include="Security\SymmetricEncryption\AeadCryptographyProvider.cs" />
     <Compile Include="Security\SymmetricEncryption\LegacyRijndaelCryptographyProvider.cs" />
     <Compile Include="Security\ICryptographyProvider.cs" />