Move AES GCM crypto and PBKDF2 key derivation to Cryptography folder

Cryptography/AesGcmCrypto.cs

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+using Org.BouncyCastle.Crypto.Engines;
+using Org.BouncyCastle.Crypto.Modes;
+using Org.BouncyCastle.Crypto.Parameters;
+
+using System.Security.Cryptography;
+using System.Text;
+
+namespace RemSox.Cryptography
+{
+    public static class AesGcmCrypto
+    {
+        private const int NonceSize = 12;
+        private const int TagSize = 128;
+
+        public static byte[] Encrypt(byte[] plainData, byte[] key)
+        {
+            byte[] nonce = new byte[NonceSize];
+            RandomNumberGenerator.Fill(nonce);
+
+            GcmBlockCipher cipher = new GcmBlockCipher(new AesEngine());
+            cipher.Init(true, new AeadParameters(new KeyParameter(key), TagSize, nonce));
+
+            byte[] output = new byte[cipher.GetOutputSize(plainData.Length)];
+
+            int len = cipher.ProcessBytes(plainData, 0, plainData.Length, output, 0);
+            _ = cipher.DoFinal(output, len);
+
+            byte[] result = new byte[nonce.Length + output.Length];
+
+            Buffer.BlockCopy(nonce, 0, result, 0, nonce.Length);
+            Buffer.BlockCopy(output, 0, result, nonce.Length, output.Length);
+
+            return result;
+        }
+
+        public static string Encrypt(string text, byte[] key)
+        {
+            byte[] data = Encoding.UTF8.GetBytes(text);
+            return Convert.ToBase64String(Encrypt(data, key));
+        }
+
+        public static byte[] Decrypt(byte[] encryptedData, byte[] key)
+        {
+            byte[] nonce = new byte[NonceSize];
+            Buffer.BlockCopy(encryptedData, 0, nonce, 0, NonceSize);
+
+            int cipherLength = encryptedData.Length - NonceSize;
+            byte[] cipherBytes = new byte[cipherLength];
+
+            Buffer.BlockCopy(encryptedData, NonceSize, cipherBytes, 0, cipherLength);
+
+            GcmBlockCipher cipher = new GcmBlockCipher(new AesEngine());
+            cipher.Init(false, new AeadParameters(new KeyParameter(key), TagSize, nonce));
+
+            byte[] plain = new byte[cipher.GetOutputSize(cipherBytes.Length)];
+
+            int len = cipher.ProcessBytes(cipherBytes, 0, cipherBytes.Length, plain, 0);
+            _ = cipher.DoFinal(plain, len);
+
+            return plain;
+        }
+
+        public static string Decrypt(string cipherText, byte[] key)
+        {
+            byte[] data = Convert.FromBase64String(cipherText);
+            byte[] plain = Decrypt(data, key);
+            return Encoding.UTF8.GetString(plain);
+        }
+    }
+}

Cryptography/CryptoManager.cs

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+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Numerics;
+using System.Threading.Tasks;
+using Cosmos.Kernel.System.Keyboard;
+using Cosmos.Kernel.System.Mouse;
+using RemSox.Plugs;
+
+namespace RemSox.Cryptography;
+
+public static class CryptoManager
+{
+    private static Point lastMousePosition = new Point(0, 0);
+
+    public static void Update()
+    {
+        int x = MouseManager.X;
+        int y = MouseManager.Y;
+        int dx = x - lastMousePosition.X;
+        int dy = y - lastMousePosition.Y;
+        int dz = MouseManager.ScrollDelta;
+
+        lastMousePosition = new Point(x, y);
+
+        RandomNumberGeneratorImplementationImpl.AddMouseEntropy(dx, dy, dz, x, y);
+
+        if (!KeyboardManager.KeyAvailable) return;
+
+        KeyEvent keyEvent = KeyboardManager.Peek();
+
+        RandomNumberGeneratorImplementationImpl.AddKeyboardEntropy((uint)keyEvent.Key, (uint)keyEvent.Modifiers, keyEvent.KeyChar);
+    }
+}

Cryptography/PasswordKeyDeriver.cs

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+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Generators;
+using Org.BouncyCastle.Crypto.Parameters;
+
+namespace RemSox.Cryptography
+{
+    public static class Pkcs5S2PasswordKeyDeriver
+    {
+        private const int KeySize = 32; // 256-bit key
+        private const int Iterations = 150_000; // PBKDF2 cost factor
+
+        public static byte[] DeriveKey(string password, byte[] salt)
+        {
+            Pkcs5S2ParametersGenerator generator = new Pkcs5S2ParametersGenerator(new Sha256Digest());
+
+            generator.Init(
+                PbeParametersGenerator.Pkcs5PasswordToBytes(password.ToCharArray()),
+                salt,
+                Iterations
+            );
+
+            return ((KeyParameter)generator.GenerateDerivedMacParameters(KeySize * 8))
+                .GetKey();
+        }
+    }
+}