GCNet is a Grand Chase networking library created by SyntaxDev which provides cryptography and packet-related features.
The CoreLib assembly provides some core features like packet encryption and decryption, packet authentication with HMAC and key generation.
The PacketLib assembly gives an I/O packet managing by providing compression, data reading and writing in addition to the own cryptography functions.
To build the project, you should use Visual Studio 2015 with .NET Framework 4.5.2.