Tags: hash programming bruteforce prog js
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# Full WriteUp
Full Writeup on our website: [http://www.aperikube.fr/docs/inshack_2018_visual_hashing_hard](http://www.aperikube.fr/docs/inshack_2018_visual_hashing_hard)
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# TL;DR
In this challenge, we had a browser extension which made 4 color on user input for a given input and a screenshot of a password with the associated colors.
This kind of coloration can be compared with a "visual hashing" of the password: each text input has his own colors.
We had to first reverse the web extension: the color was made with a SHA1() of the input which was translated to 4 colors in hexadecimals.
The final step of the algorithm was adding few random on the colors (+/- 3 shade of red, green and blue).
To accomplish the task, we had only 5 chars to bruteforce, compute the 4 colors for each pass and verify that each colors correspond to te original one (+/- 3 tone).