Ask HN: How can I learn computer security?
Cyber pro here - 5 years doing IV&V testing, 15 years as Fed, State and Local contractor, now a firewall admin at a major U.S. uni.  I got an NSA accredited (https://www.nsa.gov/resources/educators/centers-academic-exc...) Master's in IT with a specialization in security.  While the degree got my foot in the door (I have a BA in Arts - but have been messing around with computers since the early 80's - plus a lot of self taught stuff) - I've found that a ton of side reading (anything related to the subject - I spent a lot of time on the RFCs - that stuff I use every day)), looking at PCAPs to understand the protocols and reading case studies are the best way to hone the craft.For a while I was doing Governance, Risk and Compliance (GRC) work, but have always loved being a network security engineer, so I went back to that.Also - I have a CISSP, which opens a lot of doors.  I know that it is being knocked a bit nowadays, and there are certainly a some who are test knowledgeable but no hands-on, common sense experience.  I still find it valuable enough to maintain.Set up a lab - 2-4 computers and a switch should do (you could virtualize some/all of it) and work on all aspects of the TCP/IP stack if you're interested in netsec.If appsec is your thing, spend a lot of time looking at good and bad code, plus reading on-line of good and bad appsec.IF GRC is up your alley - read NIST 800-53, HIPPA, PCI-DSS, SANS Top 20 and GDPR - to understand the full breadth of controls and risk mitigation.As far as data science python and pandas are all over the industry, R not so much.  There is a big push for ML/AI work, but it might be snake-oil, time will tell.  I use a lot of python and pandas for log and flow analysis.Also - learn Linux CLI; grep, sed and awk can save your butt in most situations.  Gray beard stuff will come later.Good luck!