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.
Each lesson works two ways. Students can work through the online tutorial at their own pace (it checks their answers and saves their progress in their browser), or you can teach it to the whole class from the slides, then send students into the tutorial for the Modify and Make steps.
Every lesson guide has plain-language notes, the answers to every check, a solution for every task, and slides and a worksheet for Waypoints Prepare. These guide pages are not linked from student pages, but they are not secret either: keep printed Teacher editions for answers you do not want students to find.
Whole-course cheat sheet: Open to print (every command, grouped by unit: a handout for the final challenge)
Wired and wireless links, and how messages travel as numbered packets.
A network joins computers so they can send data. Links can be wired (cable, fibre) or wireless (Wi-Fi, mobile). Three properties decide how well a link works: bandwidth (how much data each second, in megabits a second), latency (the delay for one packet, in milliseconds) and reliability (how many packets get lost). Cables usually win on all three; wireless wins on freedom to move.
Data is not sent as one long stream. It is split into packets, each numbered and addressed. Routers pass each packet on, and packets may take different routes, arrive out of order, or get lost at a busy router. The TCP protocol has the receiver confirm each packet; anything not confirmed is sent again, and the numbers put the message back in order.
bandwidth, latency, reliability, packet, router, protocol, TCP, acknowledgement.
Cheat sheet: Open to print (A4, with board pictures) · Markdown
Why data needs encrypting on its way, and the whole journey of a message across the internet.
Packets pass through equipment you don't control: the café's Wi-Fi, your internet provider, routers in other countries. Anyone along the way can copy them, so anything sent as plain text (a password, a card number) can be read. Encryption scrambles the data with a key before it leaves your device; only someone with the key can reverse it. Encryption has to be reversible, or the receiver couldn't read it either.
On the web, HTTPS (the padlock) encrypts everything between your browser and the website. A purchase online is the whole chain at once: encrypted on your laptop, split into packets, sent over Wi-Fi then cables, routed, resent if lost (TCP), put back in order and decrypted by the shop.
The Code pathway's Secret messages course builds ciphers (Caesar, XOR), cracks them and shares keys on micro:bits. These lessons show what encryption is for; that course shows how ciphers work.
encryption, decryption, key, plain text, cipher text, HTTPS, eavesdropper.
Cheat sheet: Open to print (A4, with board pictures) · Markdown
Find four flags in the club's own network traffic, then fix it.
Cheat sheet: Open to print (A4, with board pictures) · Markdown