A lightweight, high-performance WebSocket client built from scratch, implementing the full WebSocket RFC 6455 handshake, framing logic, masking, and TLS encryption — without using any external WebSocket libraries.

This client connects to secure WSS servers, performs the HTTP Upgrade handshake, encrypts packets using OpenSSL, and handles full-duplex messaging.

Implements the protocol manually:

• HTTP Upgrade → 101 Switching Protocols
• Base64 nonce generation
• Frame masking/unmasking
• Bit-level frame construction
• Opcode handling

Uses OpenSSL for TLS handshaking and encrypted communication.

Built using:

• Winsock2
• CMake
• MSVC (Visual Studio)
• vcpkg for dependency management

Separated into:

• websocket_client.*
• tls_context.*
• cli.*
• tests/

• C++17
• Windows API (Winsock2)
• OpenSSL (via vcpkg)
• CMake Build System
• MSVC Toolchain

vcpkg install openssl:x64-windows

mkdir build
cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=C:/Users/ershe/vcpkg/scripts/buildsystems/vcpkg.cmake -A x64

cmake --build build --config Release

./build/Release/websocket_client.exe

• HTTP Upgrade handshake
• Sec-WebSocket-Key + Base64
• Accept hash using SHA-1
• Opcode handling

• TLS handshake
• Certificate validation
• OpenSSL BIO socket integration

• Winsock socket creation
• Address resolution
• TCP stream communication

• ASN.1 compliant masking
• Payload segmentation
• Frame packing/unpacking

Inside tests/:

• Automated connect / send / receive test
• Asserts handshake success
• Tests echo server consistency

Run manually:

./build/Release/websocket_tests.exe

SecureWebSocketClient-Cpp
│ CMakeLists.txt
│ LICENSE
│
├── src
│ ├── main.cpp
│ ├── cli/
│ │ cli.h
│ │ cli.cpp
│ └── websocket/
│ websocket_client.h
│ websocket_client.cpp
│ tls_context.h
│ tls_context.cpp
│
└── tests/
 websocket_client_test.cpp

This project is licensed under the MIT License.

Shehzan Khan