- https://trailofbits.github.io/ctf/ - CTF Field Guide
online CTF
- https://microcorruption.com/login - Embedded Security CTF
- https://picoctf.com/ with option for teachers https://picoctf.com/teachers - 'picoCTF is a computer security game targeted at middle and high school students.'
- https://ctf.isis.poly.edu/
Past CTF
- http://captf.com/practice-ctf/ - Practice CTF List / Permanent CTF List
- http://captf.com/ - CTF materials