links: GitHub - ZK-Hack/puzzle-gamma-ray my github repo mnt paper A log of my thoughts while solving ZK Hack IV puzzle 1. initial pass notes and unpacking ConstraintSynthesizer are quite messy, but remain here for posterity. Skip to header [[#in review]] for the "knowledge clean-up" phase of the log

What happened: On Monday, August 8 2022, the US Department of Treasury's Office of Foreign Assets Control (OFAC) sanctioned Ethereum-based cryptocurrency mixer Tornado Cash on grounds of its use in money laundering. OFAC also sanctioned any funds currently in the Tornado Cash, meaning any funds withdrawn on or after August 8th are to be "frozen", requiring any recipient of such funds to block and/or forfeit those funds, to avoid violation of OFAC sanctions. Since cryptocurrency transactions are unblockable, this ruling puts the onus on Ethereum users to verify that they have not received funds from a Tornado cash address. Stablecoin provider USDC Circle immediately complied by blocking all listed SDN Tornado Cash addresses. Github immediately removed the Tornado-cash organization from their site. Then on Friday, August 12 2022, Dutch authorities arrested 29-year old developer Alexey Pertsev on grounds of his suspected work on Tornado Cash. (U.S. Treasury Sanctions Notorious Virtual Currency Mixer Tornado Cash | U.S. Department of the Treasury) (5 Things to Know About OFAC Sanctioning Crypto Mixer Tornado Cash)