My writeup for the National Cyber Scholarship Competition 2021
Download the file and find a way to get the flag.
Contents: cm02.txt
This challenge simply provides a text file which seems to have a message encoded in emojis. It seems to be a simple substitution cipher, leaving punctuation. Although there are many tools that are useful for substitution ciphers, I loaded it Cyberchef as an environment for testing my key, and ran it through a few online tools to get frequency of standard letters as well as digraphs and trigraphs (combinations of two and three letters in words). I used online resources that displays a standard English letter frequency chart, as well as an English frequency chart of digraphs, trigraphs, two letter words, and three letter words. I played around with replacing letters and eventually got to a recipe that decoded enough characters to show that it is a passage about electricity, with the flag embedded inside:
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flag: frequently_substitute_frowny_face_for_smiley_face
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