Picoctf Substitution-50 Write Up

There's an authorization code for some Thyrin Labs information here, along with someone's favorite song. But it's been encrypted! Find the authorization code. encrypted.txt

This question requires you to use brute force to find the correct substitution cipher.

I googled for quite some time and came up with this site http://quipqiup.com/

Copy-paste one line at a time from the text and click solve. Then note down the substitutions which make sense from the examples given below.

Once you have most of the letters and the substitutions for those letters, you can go to this site https://www.iam.unibe.ch/~run/frequencies.php and fill up the boxes and get your text back to its original form.

And when you use the cipher to substitute the first line of the text given

ie KVEFQKVSNOJFKOSDRSPEOLHEBNEBFNEP

, you get 'theauthorizationcodeisHeprepared' which is your answer

Flag:theauthorizationcodeisHeprepared

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