## Introduction

Speak Freely is an Internet telephone for Microsoft Windows that allows you, with appropriate hardware and software, to send and receive audio, in real time, over a computer network. If you're connected to the Internet by a sufficiently high-speed link, you can converse with anybody else similarly connected anywhere on Earth without paying long-distance phone charges. Users can find one another, even if they have dial-up connections to the Internet, by publishing and searching directory entries on a Look Who's Listening server. You can designate a bitmap file to be sent to users who connect so they can see who they're talking to.

Speak Freely is better than using your regular telephone not only because you aren't running up your phone bill, but also because your conversation is secure from eavesdroppers. Speak Freely provides three different kinds of encryption, including the same highly-secure IDEA algorithm PGP uses to encrypt message bodies. By using PGP to automatically exchange session keys, you can Speak Freely to total strangers, over public networks, with greater security than most readily available telephone scramblers provide.

Speak Freely for Windows is 100% compatible Speak Freely for Unix, currently available for a variety of Unix workstations. Windows users can converse, over the Internet, with users of those Unix machines. In addition, Speak Freely supports the Internet Real-Time Protocol (RTP) and the original protocol used by the Lawrence Berkeley Laboratory's Visual Audio Tool (VAT); by selecting the correct protocol, you can communicate with any other network voice program which conforms to one of these standards.

Multicasting is implemented, allowing those whose networks support the facility to create multi-party discussion groups to which users can subscribe and drop at will. For those without access to Multicasting, a rudimentary Broadcast capability allows transmission of an audio feed to multiple hosts on a fast local network.