A laptop left on a train
A sales worker leaves a laptop on a train. It holds a list of 4,000 customers.
If the disk is locked with a key, the thief sees only noise. If it is not, every name is read.
Today you choose the right lock for the right job.
By the end of this lesson
Note
I can choose the right lock for data on the move and for data in storage.
Key words
| Word | What it means |
|---|---|
| Encryption | turning data into a secret code with a key |
| Asymmetric | uses a pair of keys: one public and one private |
| Symmetric | uses the same key to lock and unlock |
| In transit | data that is moving from one place to another |
| At rest | data that is stored and not moving |
| TLS | the modern way to lock a web or email link |
| SSL | the older way, now replaced by TLS |
| Full disk encryption | locks everything on a device |
| File encryption | locks single files or folders |
The cells students fill in are left blank in this preview.
Starter
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Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Asymmetric tools protect data in transit
Data in transit can be read by anyone along the road. You cannot share a secret key safely with a stranger.
So the web uses asymmetric keys to start a safe link. The two sides agree a secret, then lock the data.
This is how a card number crosses to a shop. It is also how encrypted email works.
Tools for data in transit
| Tool | What it does | Where you see it |
|---|---|---|
| TLS | Locks the link from end to end | Websites, email, chat |
| SSL | An old tool. Now replaced by TLS | Old sites. Turn it off |
| Encrypted email | Only the receiver's private key opens it | Messages with private data |
The cells students fill in are left blank in this preview.
Check
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Check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.