This TED Talk features cryptographic researcher Craig Costello, recorded live at TEDx Sydney, 2019.

I'm in the business of safeguarding secrets, and this includes your secrets.

Cryptographers are the first line of defense in an ongoing war that's been raging for centuries,

a war between code makers and code breakers, and this is a war on information.

The modern battlefield for information is digital, and it wages across your phones, your computers,

and the internet.

Our job is to create systems that scramble your emails and credit card numbers,

your phone calls and text messages, and that includes those saucy selfies.

So that all of this information can only be descrambled by the recipient that it's intended for.

Now, until very recently, we thought we'd won this war for good.

Right now, each of your smartphones is using encryption that we thought was unbreakable,

and it was going to remain that way.

We were wrong, because quantum computers are coming and they're going to change the game

completely.

Throughout history, cryptography and code breaking has always been this game of cat and mouse.

Back in the 1500s, Queen Mary the Scots thought she was sending encrypted letters that only her soldiers could decipher.

But Queen Elizabeth of England, she had codebreakers that were all over it.

They decrypted Mary's letters, saw that she was attempting to assassinate Elizabeth

and subsequently they chopped Mary's head off.

A few centuries later, in World War II, and subsequently they chopped Mary's head off.

A few centuries later, in World War II,

the Nazis communicated using the Enigma code,

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