Networks and security: Digital systems

Networks follows AC9TDI8K02 (Years 7–8): wired and wireless links, packets and TCP, why data needs encrypting, and the whole journey of a message. The Code pathway's Secret messages course (MakeCode) builds, cracks and shares ciphers; these lessons show what encryption is for. Security and privacy (Years 9–10, AC9TDI10K01): the operating system, names and addresses, sign-in and permissions, hashes and keys, then a capture-the-flag finale. Cyber safety and privacy covers the Processes strand's privacy and security descriptors as missions on a made-up club app: Years 7–8 AC9TDI8P13 (passwords, second factors, phishing) and AC9TDI8P14 (digital footprint), Years 9–10 AC9TDI10P13 (threat models, kinds of weakness) and AC9TDI10P14 (the Australian Privacy Principles), then a security review that earns flags. It is defensive throughout. Capture the flag (Years 8–10) adds two skills, encoding is not encryption and what your own page gives away, then a capture the flag on the club's old archive that uses decoding, page source, the command line and the tiny processor. For more capture-the-flag practice beyond this site, picoCTF (Carnegie Mellon) is free for school students; check its account and age requirements first.

Foundations

NetworksFollow a packet across the internet.How data travels between computers and how it is kept safe: wired and wireless links, packets and the TCP protocol, why data needs encrypting on the way, and the whole journey of a message across the internet. Then a capture the flag on the club's own network.Cyber safety and privacyKeep the club's app, and yourself, safe.You are the security officer for the Coding Club's new app. Years 7–8: why passwords fail, how a second factor protects an account, spotting phishing, and keeping a digital footprint small. Years 9–10: a threat model of the app, the three kinds of weakness, and the Australian Privacy Principles. Then a security review: find and fix every weakness to earn the flags. Everything is defensive and fictional.

Extensions

Capture the flagFind what's exposed before anyone else does.Years 8–10. Two skills a defender needs, then a capture the flag that uses everything: encoding is not encryption (binary, hex and base64 are public rules anyone can undo), and what your own web page gives away (comments, hidden fields, scripts and photo details reach every visitor). Then the old club archive: five flags found with decoding, page source, the command line, a tiny processor and a key word, and the leaks fixed before it closes. Defensive and fictional throughout.After: Cyber safety and privacy and Networks and How a web page is made Security and privacyWhat keeps your data safe, and what doesn't.For Years 9–10: how the operating system manages hardware and access, how names and addresses get data to the right computer, how sign-in and permissions decide who may do what, and how hashes and public keys protect passwords and messages. Then a capture-the-flag finale: find the weaknesses in a school portal and fix them.After: Networks