fix #27: compatibility with Mono/Android

src/Client.cs

@@ -369,7 +369,7 @@ namespace WTelegram
 			{
 				lock (_session) _session.Save();
 			}
-			Helpers.Log(2, $"Connected to {(TLConfig.test_mode ? "Test DC" : "DC")} {TLConfig.this_dc}... {TLConfig.flags & (Config.Flags)~0xE00}");
+			Helpers.Log(2, $"Connected to {(TLConfig.test_mode ? "Test DC" : "DC")} {TLConfig.this_dc}... {TLConfig.flags & (Config.Flags)~0xE00U}");
 		}
 
 		/// <summary>Obtain/create a Client for a secondary session on a specific Data Center</summary>

src/Session.cs

@@ -39,6 +39,7 @@ namespace WTelegram
 		private readonly DateTime _sessionStart = DateTime.UtcNow;
 		private readonly SHA256 _sha256 = SHA256.Create();
 		private Stream _store;
+		private byte[] _reuseKey;   // used only if AES Encryptor.CanReuseTransform = false (Mono)
 		private byte[] _encrypted = new byte[16];
 		private ICryptoTransform _encryptor;
 		private Utf8JsonWriter _jsonWriter;
@@ -83,6 +84,7 @@ namespace WTelegram
 			session._store = store;
 			Encryption.RNG.GetBytes(session._encrypted, 0, 16);
 			session._encryptor = aes.CreateEncryptor(rgbKey, session._encrypted);
+			if (!session._encryptor.CanReuseTransform) session._reuseKey = rgbKey;
 			session._jsonWriter = new Utf8JsonWriter(session._jsonStream, default);
 			return session;
 		}
@@ -98,6 +100,9 @@ namespace WTelegram
 			_encryptor.TransformBlock(_sha256.ComputeHash(utf8Json, 0, utf8JsonLen), 0, 32, _encrypted, 16);
 			_encryptor.TransformBlock(utf8Json, 0, encryptedLen - 64, _encrypted, 48);
 			_encryptor.TransformFinalBlock(utf8Json, encryptedLen - 64, utf8JsonLen & 15).CopyTo(_encrypted, encryptedLen - 16);
+			if (!_encryptor.CanReuseTransform) // under Mono, AES encryptor is not reusable
+				using (var aes = Aes.Create())
+					_encryptor = aes.CreateEncryptor(_reuseKey, _encrypted[0..16]);
 			_store.Position = 0;
 			_store.Write(_encrypted, 0, encryptedLen);
 			_store.SetLength(encryptedLen);

src/TL.Secret.cs

@@ -363,7 +363,7 @@ namespace TL
 			/// <summary>Random message ID of the message this message replies to (parameter added in layer 45)</summary>
 			[IfFlag(3)] public long reply_to_random_id;
 
-			[Flags] public enum Flags
+			[Flags] public enum Flags : uint
 			{
 				/// <summary>Field <see cref="reply_to_random_id"/> has a value</summary>
 				has_reply_to_random_id = 0x8,
@@ -503,7 +503,7 @@ namespace TL
 			/// <summary>Random group ID, assigned by the author of message.<br/>Multiple encrypted messages with a photo attached and with the same group ID indicate an <a href="https://corefork.telegram.org/api/files#albums-grouped-media">album or grouped media</a> (parameter added in layer 45)</summary>
 			[IfFlag(17)] public long grouped_id;
 
-			[Flags] public enum Flags
+			[Flags] public enum Flags : uint
 			{
 				/// <summary>Field <see cref="reply_to_random_id"/> has a value</summary>
 				has_reply_to_random_id = 0x8,

src/TL.cs

@@ -39,14 +39,14 @@ namespace TL
 			writer.Write(ctorNb);
 			IEnumerable<FieldInfo> fields = type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
 			if (tlDef.inheritBefore) fields = fields.GroupBy(f => f.DeclaringType).Reverse().SelectMany(g => g);
-			int flags = 0;
+			uint flags = 0;
 			IfFlagAttribute ifFlag;
 			foreach (var field in fields)
 			{
-				if (((ifFlag = field.GetCustomAttribute<IfFlagAttribute>()) != null) && (flags & (1 << ifFlag.Bit)) == 0) continue;
+				if (((ifFlag = field.GetCustomAttribute<IfFlagAttribute>()) != null) && (flags & (1U << ifFlag.Bit)) == 0) continue;
 				object value = field.GetValue(obj);
 				writer.WriteTLValue(value, field.FieldType);
-				if (field.Name == "flags") flags = (int)value;
+				if (field.Name == "flags") flags = (uint)value;
 			}
 		}
 
@@ -63,14 +63,14 @@ namespace TL
 			var obj = Activator.CreateInstance(type);
 			IEnumerable<FieldInfo> fields = type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
 			if (tlDef.inheritBefore) fields = fields.GroupBy(f => f.DeclaringType).Reverse().SelectMany(g => g);
-			int flags = 0;
+			uint flags = 0;
 			IfFlagAttribute ifFlag;
 			foreach (var field in fields)
 			{
-				if (((ifFlag = field.GetCustomAttribute<IfFlagAttribute>()) != null) && (flags & (1 << ifFlag.Bit)) == 0) continue;
+				if (((ifFlag = field.GetCustomAttribute<IfFlagAttribute>()) != null) && (flags & (1U << ifFlag.Bit)) == 0) continue;
 				object value = reader.ReadTLValue(field.FieldType);
 				field.SetValue(obj, value);
-				if (field.Name == "flags") flags = (int)value;
+				if (field.Name == "flags") flags = (uint)value;
 				else if (field.Name == "access_hash") reader.Client?.UpdateAccessHash(obj, type, value);
 			}
 			return (IObject)obj;
@@ -108,6 +108,8 @@ namespace TL
 						writer.Write(int256);
 					else if (value is IObject tlObject)
 						WriteTLObject(writer, tlObject);
+					else if (type.IsEnum) // needed for Mono (enums in generic types are seen as TypeCode.Object)
+						writer.Write((uint)value);
 					else
 						ShouldntBeHere();
 					break;