From f6c490fc6282823af0de606ead83865a88acf62f Mon Sep 17 00:00:00 2001
From: David Sparer <sparerd@gmail.com>
Date: Thu, 13 Oct 2016 17:17:34 -0600
Subject: [PATCH] Created a key derivation interface and initial Pkcs5
 implementation

---
 .../KeyDerivation/IKeyDerivationFunction.cs   |  8 +++++
 .../KeyDerivation/Pkcs5S2KeyGenerator.cs      | 31 +++++++++++++++++++
 mRemoteV1/mRemoteV1.csproj                    |  2 ++
 3 files changed, 41 insertions(+)
 create mode 100644 mRemoteV1/Security/KeyDerivation/IKeyDerivationFunction.cs
 create mode 100644 mRemoteV1/Security/KeyDerivation/Pkcs5S2KeyGenerator.cs

diff --git a/mRemoteV1/Security/KeyDerivation/IKeyDerivationFunction.cs b/mRemoteV1/Security/KeyDerivation/IKeyDerivationFunction.cs
new file mode 100644
index 00000000..5b081e93
--- /dev/null
+++ b/mRemoteV1/Security/KeyDerivation/IKeyDerivationFunction.cs
@@ -0,0 +1,8 @@
+
+namespace mRemoteNG.Security.KeyDerivation
+{
+    public interface IKeyDerivationFunction
+    {
+        byte[] DeriveKey(string password, byte[] salt);
+    }
+}
\ No newline at end of file
diff --git a/mRemoteV1/Security/KeyDerivation/Pkcs5S2KeyGenerator.cs b/mRemoteV1/Security/KeyDerivation/Pkcs5S2KeyGenerator.cs
new file mode 100644
index 00000000..2bc3c907
--- /dev/null
+++ b/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;
+        }
+    }
+}
\ No newline at end of file
diff --git a/mRemoteV1/mRemoteV1.csproj b/mRemoteV1/mRemoteV1.csproj
index 7ea62e8e..1cc36857 100644
--- a/mRemoteV1/mRemoteV1.csproj
+++ b/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" />