Videos
Cyber security
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16 video lessons
2:08
Lesson 1
Security, privacy and integrity
Three words get used as if they meant the same thing, and the exam asks you to separate them. Security is about keeping data and systems safe from people who…
2:10
Lesson 2
Malware
Malware is any program written to harm a computer or steal from it, and the exam names six kinds. Six names is a list to memorise unless you group them. Group…
2:06
Lesson 3
Attacks and brute force
Beyond malware, attackers go at a system directly. A brute-force attack tries every possible password until one works — no cleverness, just patience and a fast…
2:00
Lesson 4
Social engineering
Everything so far has attacked the machine. But the weakest part of a system is usually not the machine — it is a person, who can simply be asked. Social…
2:04
Lesson 5
Defending a system
Defences are usually given as a list, and that hides the point. Draw them as rings instead. An attacker coming from outside meets one wall after another: the…
1:56
Lesson 6
Passwords and authentication
Authentication means proving you are who you claim to be, and there are three classic ways. Something you know — a password or a PIN. Something you have — your…
2:08
Lesson 7
Storing passwords safely
Start with what must never happen. If a site stores passwords as plain text and is breached, every password is readable the moment the file leaves the…
1:43
Lesson 8
Encoding is not encryption
People say "encoded" when they mean "encrypted", and the two are not the same thing. Encoding changes the FORMAT of data so it can be stored or sent. It is not…
2:00
Lesson 9
Symmetric encryption
Encryption scrambles a message so that only someone with the key can read it. In symmetric encryption there is one key, and it does both jobs — watch, it…
2:08
Lesson 10
Asymmetric encryption
Last lesson ended on a problem: you must share the secret key first. Asymmetric encryption answers it by using two keys instead of one. There is a public key…
1:34
Lesson 11
Hashing and digital signatures
In lesson seven we hashed passwords for secrecy. The same function does a second job: it protects integrity, which means proving that data was not changed.…
2:05
Lesson 12
HTTPS, TLS and certificates
Start with something you look at every day. When the address begins with H T T P S and a padlock appears, your connection to that site is encrypted — nobody…
1:29
Lesson 13
Data integrity
Integrity means data stays accurate, and two techniques protect it. They sound alike and the exam loves separating them, so watch what each one asks.…
2:01
Lesson 14
SQL injection
Most apps look up a user by building a query out of a string. You type your name into a box, and the app glues what you typed into the query. Type Mei, and the…
1:51
Lesson 15
Access control and least privilege
Least privilege says: give every person and every program only the access they need, and no more. The reason is not tidiness — it is what happens after…
2:13
Lesson 16
Ethics, law and staying safe
You have spent fifteen lessons learning how attacks work, and that knowledge comes with a duty. A computing professional uses these skills to protect people…