Video conferencing is a powerful tool that enables face-to-face, real-time communications between associates around the world. A business executive in Boston can hold a virtual meeting with his factory managers in China. A sales manager can demonstrate a new product to sales reps spread out across the country. Or, military commanders in the Pentagon can send new orders to soldiers in the field.

© Photographer: Andres Rodriguez | Agency: Dreamstime.com Video conferencing lets associates communicate from different locations.

Security is crucial to video conferencing. During a video conference, sensitive information and data travels across internal and external networks where it's susceptible to the prying eyes of hackers -- or in the case of the military, the enemy. If a network is hacked, the video-conference stream becomes the hacker's own private surveillance camera, recording and re-broadcasting corporate secrets and top-secret intelligence [source: Wired].

Video-conferencing security is not only in a company's best interest -- it's the law. Recent government regulations like the Health Insurance Portability and Accountability Act (HIPAA) and the Sarbanes-Oxley Act of 2002 require that medical providers, financial institutions and other corporations secure all electronic data associated with their customers and patients [source: Centers for Medicare & Medicaid Service]. That includes all electronic transmissions of personal client data, even video conferences.

Since the terrorist attacks of Sept. 11, 2001, government and military agencies have also been required to comply with strict security protocols for all electronic transmissions [source: Military Information Technology]. The National Security Agency (NSA) and the Defense Information Systems Agency (DISA) have set guidelines for military video conferences wherein all transmissions are protected by several redundant layers of encryption.

In this HowStuffWorks article, we'll explain the basic concepts of video-conferencing security when using ISDN (phone line) networks.

Let's start by defining some basic concepts related to video-conferencing security.