UDP Socket Manager

Overview

UDP-based Socket Manager for secure communication using asymmetric and symmetric encryption is a wrapper over UDP. It uses Protocol Buffers for message encoding and supports DTLS for secure communication.

How It Works

1. Client Fetches Server Public Key – The client retrieves the server’s public key.
2. Client Hello – The client sends a hello message containing a random value and an AES-CBC key, encrypted with the server’s public key.
3. Server Hello Verify – The server responds with a helloverify message containing a cookie HMAC, using the AES-CBC key from the client.
4. Client Verification – The client resends the hello message with the cookie HMAC, AES-CBC key, and a verification token.
5. Server Hello – The server completes the handshake by sending a session ID.
6. Session Maintenance – The client continues communication while maintaining heartbeat messages; otherwise, the session expires.

Message Structure

Field	Description
Message Type	1 byte
Payload	... rest of the message

Message Types

    ClientHelloRecordType   = 1  
    HelloVerifyRecordType   = 2  
    ServerHelloRecordType   = 3  
    PingRecordType          = 4  
    PongRecordType          = 5  
    UnAuthenticated         = 6  

Any value greater than these can be used as a custom message type.

Docs

Socket Client docs Socket Server docs