Richard A. Clarke, formerly of the National Security Council
Cybrary — Security School & Blog
Random Bits — Cryptography Discussion Board
NMAP — Leading Network Penetration Tool & Website
Dept. Homeland Security List of Open Source Cybersecurity Tools
Bivio Networks’ List of Open Source Cybersecurity Tools
Securing Your Cloud:
Cloud Security Checklist — Courtesy ThreatStack
Cloud Security Assessment — Courtesy ThreatStack
Cloud Security Playbook — Courtesy ThreatStack
Cyber Security 411 