- Capability Based Security (NOT the permissions flags on your phone or "app") - Offers the possibility for honestly secure computing
- Data diodes (unidirectional networks) - allow you to monitor a network without allowing external control (or only submit info, never ever exfiltrate it)
- GNU Radio - you can play with your audio ports, and learn instinctively how do deal with all the stuff that used to require DSP chips... then apply that knowledge with a $30 RTL-SDR dongle.
- Lazarus - seconding the above... a really good Pascal GUI IDE. The documentation needs work, but it's pretty good otherwise.
- Data diodes (unidirectional networks) - allow you to monitor a network without allowing external control (or only submit info, never ever exfiltrate it)
- GNU Radio - you can play with your audio ports, and learn instinctively how do deal with all the stuff that used to require DSP chips... then apply that knowledge with a $30 RTL-SDR dongle.
- Lazarus - seconding the above... a really good Pascal GUI IDE. The documentation needs work, but it's pretty good otherwise.