Working with the GT3 Security Services requires, of course, a basic knowledge of certain fundamental computer security concepts. If you are already familiar with concepts such as authentication, authorization, public key cryptography, and certificate authorities, then you can safely skip this section. If you've never dealt with secure communications, or feel your knowledge of these concepts might be a bit rusty, then you should definitely read this chapter. However, take into account that this chapter is meant as an overview of these concepts. Some readers, specially complete newcomers, should consider reading some material that deals specifically with computer security: