The Trusted Setup is a vital part of what makes Zcash work. Zcash is the first coin to use a simplified implementation of a new cryptographic proof called zk-SNARKs (SNARKS for short). These SNARKS are the engine that can quickly and efficiently verify a transaction and add it to the blockchain without revealing any details to the public. The tricky thing about these SNARKS is that (like many algorithms) they need to have a one time setup. And the reason that this setup is called the “Trusted Setup” is because you have to trust that whoever generated those keys destroyed them when they were done.