Caesar shift

Every letter moves the same distance along the alphabet. Julius Caesar used a shift of three.

This is not encryption. Twenty-five possible keys. A computer tries all of them faster than you can read this sentence.

What it is made of

Is this encryption?: No. It hides text from a glance, not from a person.
Possible keys: 25
Broken since: antiquity
Runs in: Your browser and the server

What it is

Every letter moves the same distance along the alphabet. Julius Caesar used a shift of three.

Where it runs

Both lanes. By default the lab runs it in your own browser over the Web Crypto API, so nothing leaves your device — there is no upload, no size limit and no queue. The server lane is there when you want it, and it is the only way an agent or a script can reach the same engine.

Why a real encryption tool ships a broken cipher

Because this is the only kind of cipher you can run by hand, and doing that once is what makes "key" and "keyspace" mean anything. You cannot save an encrypted file with it here — the lab will not write a container claiming to protect something that anyone can read. What it will do is break the Caesar one in front of you, with no key, and show you all twenty-five wrong answers beside the right one.

Try it

Open the Classical bench in the lab and type into it. Then hand the result to the breaker and watch it come apart without a key. The lab is a Leumas membership away; everything on this page is free.