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chip’s challenge and an early childhood journey through cryptography

note: this is a story i originally posted as a thread on birdsite and i felt like i should post it somewhere else in case i lose it1, and because i want to share it again.

i put Chips Challenge on my list of games that spark joy, partially because it was that game that i had the first conscious memory of doing any type of reverse engineering. i was 8 years old. on windows 3.1.

in lieu of a save system, each level in the game had a 4 letter password you could use to skip to that level. and i wanted the passwords to all the levels. and i thought they must be in the computer somewhere, right?2

so i opened the EXE file or whatever file the data for the levels happened to be, in Wordpad. yes, Wordpad. lol. and then i scrolled thru, saw level names, and saw what SHOULD have been the passwords along with it. except. the letters were all different.

as i was trying to figure this out my childhood friend was there and i would be talking out loud my thought process (i'm pretty sure he thought i was weird at that point). we already had a list of passwords for certain levels we wrote down as we progressed. so i compared this list, with the passwords we found in wordpad and i said, there must be a correlation (or however an 8yo would describe that concept) here.

looking across the passwords i would eventually observe that the letters would be in the same position but with a different letter. so i deduced "it must be a secret code" and then started writing down what letter mapped to what until we had everything in the alphabet.

to test it out, we went all the way bottom to find the last level: 149 & try our little decoder sheet on it… the password was "DIGW". we entered that in and boom. [insert 8yo expression of mind being completely blown] (and at this point, my friend probably thought i was really cool)

to me that would spark basically the rest of my reverse engineering path, stories for another day, and a basis of how i learn and solve problems today.

a while back @aiviwave gave me this zine by Amy Wibowo (@sailorhg).

Secret messages zine

it's an amazing & very cute & very accessible to anyone - take on the subject of cryptography i highly recommend, & it brought me WAYYY back to those formative days in my childhood and i learned even more about the history predating computers, earlier in human history. Amy does a really great job of showing this in her educational zines!

  1. yes, i do have an archive. but still.
  2. this would become a common theme. e.g.,
    • "the level data must be in the ROM right? it probably looks like \[x, y, object number], what if we try these hex search patterns?"
    • "the music must be in the SPC file right? these are the notes of this song and we can assign a number for each semitone, but we don't know what notes they map to in the game. we could try a relative hex search? does that exist?".