1. Preface

This document tries to demonstrate and explain the GnuTLS library API. A brief introduction to the protocols and the technology involved, is also included so that an application programmer can better understand the GnuTLS purpose and actual offerings. Even if GnuTLS is a typical library software, it operates over several security and cryptographic protocols, which require the programmer to make careful and correct usage of them, otherwise he risks to offer just a false sense of security. Security and the network security terms are very general terms even for computer software thus cannot be easily restricted to a single cryptographic library. For that reason, do not consider a program secure just because it uses GnuTLS; there are several ways to compromise a program or a communication line and GnuTLS only helps with some of them.

Although this document tries to be self contained, basic network programming and PKI knowlegde is assumed in most of it. A good introduction to networking can be found in [STEVENS] (see section Bibliography) and for Public Key Infrastructure in [GUTPKI] (see section Bibliography).

Updated versions of the GnuTLS software and this document will be available from http://www.gnutls.org/ and http://www.gnu.org/software/gnutls/.