If you are about to start working towards the Security+ IT certification from CompTIA, I would strongly recommend downloading the exam objectives from the CompTIA web site. However, below are my study notes, mainly, so I always have the information to hand, but they may be of use if you are planning on taking the exam yourself at some stage. They should help you get started.

1. Network Security
   1. Implement Security Configuration Parameters on Network Devices
   2. Network Administration Principles
2. Compliance and Operational Security
3. Threats and Vulnerabilities
4. Application, Data and Host Security
5. Access Control and Identity Management
6. Cryptography