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picoCTF 2021 -The Numbers writeup-

Shitian Daxiang
Bio := struct {Identity, Undergrad, Research}{ "Ainu descendants", "πŸ“Š Data Science", "πŸ”¬ Privacy Preserving Data Mining"}
・1 min read


The numbers... what do they mean?


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Since { appears in the seventh character of the image, we can a find out that the flag format is picoctf{***}. This means that 16β†’P, 9β†’I, 3β†’C, 15β†’O, 3β†’C, 20β†’T, and 6β†’F are used.
And from this rule, we can assume that Letter Number Cypher (A1Z26), which converts numbers directly into alphabets, is used.

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All you need to do is decode A1Z26 with Cyberchef or convert it manually to get the flag.
But don't forget to add {} and type the flag in uppercase.


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