75 lines
2.3 KiB
C#
75 lines
2.3 KiB
C#
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using System.Security.Cryptography;
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using System.Text;
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await using Stream stream = await EncryptMessageAsync();
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await DecryptMessageAsync(stream);
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await Task.Delay(-1);
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return;
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static async Task<Stream> EncryptMessageAsync()
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{
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using var aes = Aes.Create();
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aes.GenerateKey();
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aes.GenerateIV();
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using ICryptoTransform encryptor = aes.CreateEncryptor();
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var stream = new MemoryStream();
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await using var crypto = new CryptoStream(stream, encryptor, CryptoStreamMode.Write, true);
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await using (var writer = new BinaryWriter(stream, Encoding.UTF8, true))
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{
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Console.WriteLine($"Client sending key: {BitConverter.ToString(aes.Key)}");
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Console.WriteLine($"Client sending IV: {BitConverter.ToString(aes.IV)}");
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// send key and iv unencrypted
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writer.Write(aes.Key.Length);
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writer.Write(aes.Key);
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writer.Write(aes.IV.Length);
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writer.Write(aes.IV);
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}
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await using (var writer = new BinaryWriter(crypto, Encoding.UTF8, true))
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{
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// send encrypted message
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byte[] message = "Hello, world!"u8.ToArray();
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writer.Write(message.Length);
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Console.WriteLine($"Writing {message.Length} bytes");
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writer.Write(message);
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}
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await crypto.FlushFinalBlockAsync();
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stream.Position = 0;
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return stream;
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}
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static async Task DecryptMessageAsync(Stream stream)
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{
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using var aes = Aes.Create();
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using (var reader = new BinaryReader(stream, Encoding.UTF8, true))
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{
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int keyLength = reader.ReadInt32();
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aes.Key = reader.ReadBytes(keyLength);
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int ivLength = reader.ReadInt32();
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aes.IV = reader.ReadBytes(ivLength);
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Console.WriteLine($"Server received key: {BitConverter.ToString(aes.Key)}");
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Console.WriteLine($"Server received IV: {BitConverter.ToString(aes.IV)}");
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}
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using ICryptoTransform decryptor = aes.CreateDecryptor();
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await using var crypto = new CryptoStream(stream, decryptor, CryptoStreamMode.Read, true);
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using (var reader = new BinaryReader(crypto, Encoding.UTF8, true))
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{
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int length = reader.ReadInt32();
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Console.WriteLine($"Reading {length} bytes");
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byte[] message = reader.ReadBytes(length);
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Console.WriteLine($"Server received message: {Encoding.UTF8.GetString(message)}");
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}
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}
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