Three physical challenge coins - Coin 0, Coin 1, Coin 2 - each a self-contained puzzle you solved from the coin art alone. Rank 0 was the whole point: people fought for first blood, and rank 23 got nothing but a line of text with your name on the board.

The prize was scarcity you could hold. Twenty-three of each coin were physically minted; claiming a slot took one of them off the table. Coin 0 alone logged 28 phrase solvers and 4 who ran it all the way to complete.

The prize was one of 23 real @23isreal.com email addresses. Two boards tracked it: "The 23" (ordinals 0-22, the winners) and "The 23'd" - the overflow board, where solving past the slots earned a line of text and no address.

Stage 0 was the audio above - decode the WAV to move on. Stage 1 was a ROT13 string that resolved to a cryptobin.co URL. That link is dead now, and stage 2 died with it. That link rot is exactly why this platform exists: every asset now lives on hakc.codes, byte-for-byte, forever.

› @zfasel solved the whole thing and declined his slot - rank -1 on the board, "Solved for Funsies - Did not collect."

A SecKC monthly Android reverse-engineering challenge. Install the app, decode the morse in an NFC tag, steghide the stream, overlay cipher.png to recover a key, then XOR the app's string to reach Key 1. The answer was SecKCake.

The Google Play store link is long dead. The original APK - v1.3.3.7 - is hosted here now, alongside every carrier image in the chain. The full artifact set is preserved so the puzzle stays solvable.