Offensive Computer Security by Xiuwen Liu and W. Owen Redwood.
Description:
The primary incentive for an attacker to exploit a vulnerability, or series of vulnerabilities is to achieve a return on an investment (his/her time usually). This return need not be strictly monetary—an attacker may be interested in obtaining access to data, identities, or some other commodity that is valuable to them. The field of penetration testing involves authorized auditing and exploitation of systems to assess actual system security in order to protect against attackers. This requires thorough knowledge of vulnerabilities and how to exploit them. Thus, this course provides an introductory but comprehensive coverage of the fundamental methodologies, skills, legal issues, and tools used in white hat penetration testing, secure system administration, and incident response.
Videos, lecture notes, etc.
If you have a choice between computer security and security for the 21st century Maginot Line (airports), pick the former over the latter.
You can get paid for both but with computer security, you may also make a difference.