If miners don't know the details of a transaction they have little incentive to censor it do they not? If so, can we actually not do away with mining and rely on benevolent validators who volunteer to validate transactions at no cost. What you have is an extremely fast, efficient, scalable but still largely trustless smart contract-executing system. Or am I missing a trick?
@murraci: Interesting! I agree with the part that zero-knowledge almost completely eliminates the ability for miners to censor.
However, I don't see how we could do away with mining. At least not in the short term. I'll be very interested to see what happens when Ethereum switches to Proof of Stake!
I'm kinda wondering if we would even need POS? The de-commoditisation of mining/validation is kind of a holy grail IMO. It means faster, scalable blockchains that pose a much bigger threat to highly efficient centralised systems. The addition of privacy is the final piece of the jigsaw.
It'd be bloody great if we could have a permissionless, uncensorable blockchain that was actually free-to-use - had no fees or inflation. In a system like Zcash, most of the security is found in the cryptography. The maintenance of a distributed ledger is still required to prevent double spending of course, but I'm wondering if this ledger could simply be maintained by benevolent guardians. Without the possibility of censorship, this seems secure to me and I think there's enough crypto-anarchists out there that would put themselves forward as guardians
I still have the gut feeling that I'm missing a crucial detail though! Probably somewhere around the consensus mechanism.
In some of the early discussions about Zcash we talked about a "notary" system similar to what you suggest, that would complement proof-of-work and provide defence in depth if there were any attack on the PoW system. In the end we wanted to focus more on the changes that are specific to privacy and leave that kind of experimentation to other blockchains. I personally hope that other systems with dissimilar ledger implementations adopt Zcash's zero-knowledge-based privacy features.
Everyone will follow Zcash I believe. Privacy is essential for the public blockchain eco-system to develop. I'm sure you're aware Greg Maxwell is actively working on an implementation for Bitcoin sidechains and Vitalik plans to have ZK proofs implemented on Ethereum within a year I think. But for now, you guys are flying the flag!