BigSpeed Voice Chat SDK is an easy-to-use set of client and server ActiveX components designed to build virtual private chat networks for small to medium groups, typically up to several hundreds of desktops. Based on mixed client/server and peer-to-peer technology. It provides totally secure text and voice messeging through powerful on-the-fly encryption.

BigSpeed Voice Chat SDK Features
Virtual Client-to-Client connections over physical Client/Server network
When a direct connection between two clients is impossible because of NAT limitations, a permanent virtual circuit can be established. In such a case, the server relays the packets traveling between that clients.
Highly compressed audio data for low-bandwidth connections
Silence compression with a voice activity detector
Echo suppression with a double talk detector
Audio data available in raw PCM format for visualization
Detection of input signal overloading & packet delaying on network slowdown
Capability to mute recording & playback
Instant alert & chat messaging
Direct file transfer, SOCKS proxy support
On-the-fly 128-bit AES encryption with random session keys
Client authentication at protocol level with digital fingerprints or secret keys
Client authentication at application level with username/password
Symmetric encryption mode with shared secret key
Asymmetric encryption mode with 1024-bit Public/Private keys
Elegant event-driven paradigm for easy integration into Windows applications
Responsive user interface while maintaining maximum bandwidth
Simple and well-organized set of properties, methods and events
Multi-threaded, fully self-contained ActiveX control