Lot of chit-chat about ZCASH. It is certainly a very exciting project, but all projects have pros and cons.
Here are some technicals to digest.
1) ZCASH has a special txn, that allows you to send coins just like Bitcoin, but the sender, receiver and amount are all hidden using a Zero Knowledge Proof.
2) ZCASH has a technology that has to be 'initialised' by first creating a public/private key pair. You keep the public key, but delete the private key .. You must TRUST that 'they' (the devs) have done this. (I think keeping them would be toooo dangerous, so I don't think they are lying about this.. ) To be fair they have done
https://z.cash/blog/the-design-of-the-ceremony.html to mitigate as best they can. Basically many people are involved, in many geographical locations, and no-one knows the 'whole' truth.
'With the MPC protocol, as long as at least one of the participants successfully deletes their private key shard, then the toxic waste is impossible for anyone to reconstruct. The only way the toxic waste can be reconstructed is if every participant in the protocol were dishonest or compromised.'
If ANYONE ever has those 'special' numbers they can create money on the network, they can't steal yours, but it is IMPOSSIBLE to tell..
3) ZCASH's accumulator (the thing that allows the Zero Knowledge proofs) cannot currently be pruned. You must keep track of ALL the spent hidden outputs. They may find a solution, but none has arisen yet.
4) Currently the ZCASH devs take a 20% cut of all the coins that are mined. (I mention this, because, well, hmm..)
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Currently Bitcoin is 'only' pseudonymous, but..
1) Bitcoin has 'Confidential Txns' (CT) working on a side-chain, this hides the amounts that are sent, but not the sender and receiver. It may someday be integrated into the main net. No trusted setup is required.
2) CT + Coin Join (and maybe OWAS - a new technique that may allow a whole block to be coin-joined trustlessly), gives a smaller anonymity set. You would know that one of these addresses has sent 'some amount' to one of these other addresses. If you are using OWAS, the number of addresses used in the coinjoin could be the number of txns in a block. Otherwise normal Coin Join / Coin Shuffle rules apply.
3) Bitcoin is fully pruneable. And so are the CT txns.
..
So.. all in all.. pretty exciting really. If nothing else it lights a fire under Bitcoin's ass. ;p