According to Suetonius:

[…] si qua occultius perferenda erant, per notas scripsit, id est sic structo litterarum ordine, ut nullum verbum effici posset: quae si quis investigare et persequi velit, quartam elementorum litteram, id est D pro A et perinde reliquas commutet.

Gaius Suetonius Tranquillus

Who understood that? For those who didn’t: this is the famous Caesar cipher, known by many names — Caesar shift, Caesar code, simple Caesar cipher.

But why would such a great general bother to invent a new “language”? As a general, I often had enemies who wanted to know my secret plans. One day, I wanted a solution and invented the Caesar cipher — the most modern encryption in the world. © Gaius Julius Caesar.

How does it work? It’s simple: you take each letter of a word and shift it three letters to the right, as described above. That means an A becomes a D. To make it easier (since many couldn’t read or write), I used only lowercase letters in this cipher.

Honestly, I would like to modestly say “Yes, I invented this,” but I can’t… Because when I talk about this cipher, you should also know why it’s so special. This cipher was still used centuries later; one of my successors, Augustus, used it too — with a small modification.

But if you think this is the best encryption, you are mistaken. The special thing is not that it can’t be easily cracked, but that the method to decrypt it must be kept secret to keep the code safe.

There are thousands of such methods, but always remember: Either the cipher is from me, Julius Caesar, or it was cunningly stolen from me!

Here’s a famous quote of mine about encryption:

Cras legam!

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Tomorrow I will read.

Gaius Julius Caesar