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Can you solve this devilish riddle which is used to recruit spies?

Do you belong in MI5?

Can you solve this devilish riddle which is used to recruit spies?
02 March 2018

Let’s be spies! Spies are great!

Actually, thinking about it, being a spy must be weird, because while there’s loads of fun stuff - travelling the world, dressing really nicely, having sex with everyone you even vaguely want to have sex with, getting pissed in really posh casinos - you’ve also got to kill people, and that seems like it probably leads to huge amounts of existential guilt and even huger amounts of admin. 

It might not be exactly like it is in the films - real life probably has a lot more combing through documents and a lot less baccarat - but there are things they do in films that they also do for real, like setting difficult challenges for recruits in the form of puzzles.

This is one that the British National Cyber Security Centre (NCSC) shared on the TodayProgramme as an example of something they’d set for potential recruits, although being a computer spy definitely involves less penetrative sex than being a gun-toting, debonair, baddie-punching type one.

“Thirteen rotters stole my answer and they ROTated it by 4 and then ROTated it by 10 and all I have left is Uccr ziqy hc ozz QmpsfTwfgh Uwfzg! Can you help me get my answer back?”

Fuck right off. 


’Thirteen rotters’ is a reference to ROT13, an example of a 'Caesar cypher’, where letters are replaced with ones from shifted positions in the alphabet. Like, ROT1 would replace A with B, M with N etc. ROT13, then, is something like this: 

Spacing is important, isn’t it? The gap between the M and N on the first line should be exactly halfway across the page. Ballsed that up. 

Right. Okay, so then ‘ROTated it by 4’ would mean shifting it back by four, and then ‘ROTated it by 10’ would shift it by another ten. 

So… wait, what? Did we go 13 forward then 14 back? Yes? But somehow no? Or, like 27 forward-back? Does it end up being the same as doing ROT12? Or ROT14? Really confusing, this.

You should end up with a G for that first U, anyway, but because we knew the answer we can’t 100% say for certain we’d have got there. The message then translates as “Good luck to all CyberFirst girls!”, which is a reference to a competition being run by the government to encourage more girls and women to consider cybersecurity careers.

Did you get it? Did we? Maybe? Probably not! DON’T KNOW! 

Let’s not be spies.