We academically wrote (2014) and then deployed Zcash (2016) using PGHR13, and then later Zcash upgraded to a better circuit that used Groth16. It was, to my kno

We academically wrote (2014) and then deployed Zcash (2016) using PGHR13, and then later Zcash upgraded to a better circuit that used Groth16. It was, to my knowledge, the first production system to use SNARKs, and “modern” systems like Tornado Cash Nova use basically the same ideas. ETA: I just noticed I'm responding to Madars ;)