Secure VoIP for private internet talk by encrypting voice communications on computer network. [ClosedTalk] securely transports voice data through strong encryption technology, advanced key exchange process, and user authentication using digital certificates. A gatekeeper service locates communication partners on the private/public network. [ClosedTalk] users only need the PC sound system and recipients email address to make internet talk. [ClosedTalk] is free for professional business and home uses. [ClosedTalk] users can enhance their communication productivity further by opting for a total solution which includes easy-to-use handsets, private gatekeeper for business users, and hotline support for a large user base. Version 1.4.1 now supports Vista.