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How to be a spy

With all the current cyber security threats around, it’s more important than ever for our country’s future workforce to have better skills than all the evil Masterminds out there! Watch this video to find out all about encryption and how to send secret spy messages!

So, if you want to be a spy, you’ll need to know how to send secret communications that none of your enemies can read. This can be done by replacing every letter of your message with a different one. But for the recipient to read the message, you would have to first give them the code.

A much safer message would be one where the recipient can decrypt it without you ever having to tell them how. This can be done by the message receiver giving everyone identical padlock numbers. This number encrypts any secret messages you might want to send their way.

But what if it gets intercepted by an evil Mastermind? Even though he has the padlock number and so knows how the message was encrypted, that doesn’t mean he knows how to decrypt it. Just because you can lock something mathematically, doesn’t mean you can unlock it the same way.

The most secure way is to use a really long number, say over 600 digits long. This is the method of encryption that is used when you shop online, use social media, or basically do anything on the internet!

No one has yet found a way to factorise very long numbers like these and it would take a computer thousands of years to work through all the digits in sequence and crack the code. It is possible – it just takes a very long time.

So, really the whole concept of internet security is based on the notion that factorising a number is actually quite hard. But if you do find a way, there are quite a few government agencies and evil Masterminds that might want to talk to you – because then you’d be able to break into the evil Mastermind’s social media accounts, steal their money and actually break the internet!

Maths is so central to internet security and national security that if you want to be a spy at MI5 or GCHQ, it’s essential you have a strong Maths background!