From e3eb36639aaeb83dd58e31324542265218d1b05b Mon Sep 17 00:00:00 2001
From: Timothy Schenk <admin@rainote.dev>
Date: Mon, 2 Jan 2023 12:18:38 +0100
Subject: [PATCH] Create AesProvider using Aes provided by .Net

---
 Server/AesProvider.cs | 46 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 Server/AesProvider.cs

diff --git a/Server/AesProvider.cs b/Server/AesProvider.cs
new file mode 100644
index 0000000..717ac24
--- /dev/null
+++ b/Server/AesProvider.cs
@@ -0,0 +1,46 @@
+using System.Security.Cryptography;
+using Microsoft.Extensions.Logging;
+
+namespace Server;
+
+public class AesProvider
+{
+	private readonly Aes _aes;
+	private readonly ICryptoTransform _encryptor;
+	private readonly ICryptoTransform _decryptor;
+	private readonly ILogger _logger;
+
+	public AesProvider(ILoggerFactory loggerFactory, Span<byte> key, Span<byte> iv)
+	{
+		_logger = loggerFactory.CreateLogger(nameof(AesProvider));
+		_aes = Aes.Create();
+		_aes.Key = key.ToArray();
+		_aes.IV = iv.ToArray();
+		_encryptor = _aes.CreateEncryptor();
+		_decryptor = _aes.CreateDecryptor();
+	}
+
+	public Span<byte> Encrypt(Span<byte> input)
+	{
+		using MemoryStream memoryStream = new MemoryStream();
+		using CryptoStream cryptoStream = new CryptoStream(memoryStream, _encryptor, CryptoStreamMode.Write);
+		cryptoStream.Write(input);
+		cryptoStream.Flush();
+
+		Span<byte> bytes = memoryStream.ToArray();
+
+		return bytes;
+	}
+
+	public Span<byte> Decrypt(Span<byte> input)
+	{
+		using MemoryStream memoryStream = new MemoryStream(input.ToArray());
+		using CryptoStream cryptoStream = new CryptoStream(memoryStream, _decryptor, CryptoStreamMode.Read);
+		Span<byte> bytes = new byte[input.Length];
+		var i = cryptoStream.Read(bytes);
+		if (i > 0)
+			_logger.LogWarning("CryptoStream hasn't been read till the end. ({length}", i);
+
+		return bytes;
+	}
+}
\ No newline at end of file