Hi all and thanks for all your feedback.
First of all some correction on the terminology as there's a great deal of confusion here. Zcoin is the coin, Zerocoin is the paper that outlines the technology. Zcash is the coin, Zerocash is the paper.
Despite the similar names they're not forks of each other and rely on different cryptographic principles and code.
Zcash was never formerly known as Zcoin.The site zerocoin.org is owned by Ian Miers @imichaelmiers one of the authors in both Zerocoin and Zerocash papers (and now is a Zerocash co-founder hence the link to Zerocash).
Zcoin implements the Zerocoin paper (
http://spar.isi.jhu.edu/~mgreen/ZerocoinOakland.pdf), Zcash implements the Zerocash paper (
http://zerocash-project.org/media/pdf/zerocash-extended-20140518.pdf).
Different papers with different cryptographic implementations though the papers share common authors. Zerocash's paper indeed begins with an introduction of Zerocoin as well.
Our coin has a working implementation of Zerocoin minting (meaning anonymity feature is working) and you can already do this within our wallet and test it our for yourself!
Although Zerocash is a development from Zerocoin meant to address certain perceived shortcomings of Zerocoin, they are not simple forks of each other and rely on different protocols.
Zerocash was meant to improve on Zerocoin on these issues:
a) Zerocoin still requires a basecoin to convert back before being allowed to spend. Zerocash has no more basecoin
b) Zerocash's proofs are much more efficient and smaller than Zerocoin's
c) Zerocoin uses fixed denominations to mint (1, 25, 50, 100) while Zerocash is not subject to such limitations
d) Greater anonymity with Zerocash since sender/receiver/amount are all obscured.
However Zerocoin's advantage over Zerocash are as follows:
a) While still retaining the basecoin and a lot of the Bitcoin core code, it is a lot easier to integrate to existing Bitcoin merchants/etc.
b) Although Zerocoin's proofs are larger and occupies more storage space, the computational requirements to generate a private transaction are many times faster. Zcash requires large amounts of RAM and minutes of computational time. Zerocoin requires seconds to use and is not memory intensive. Basically Zerocoin uses more storage space but is computationally much less intensive.
c) Parameter generation for both Zcoin and Zcash requires a trusted setup but Zcoin's parameters are arguably less controversial. (
https://github.com/zcoinofficial/zcoin/wiki/Parameters-in-set-up-phase-for-Zerocoin-in-ZCoin). A zero trust parameter setup is also within our roadmap.
d) Most importantly is that in Zcoin, total supply is still visible so if there's a flaw and someone is secretly creating coins for themselves, this can be much more easily detected. With Zcash, if a flaw is exploited, it may be almost impossible to detect as someone can mint coins for themselves without being detected.
e) Zerocoin's tech is much more reviewed and better understood than Zcash's. Zcash's use of zero knowledge proofs uses ZK-Snarks is much more experimental and only a handful of people understand it.
Here at Zcoin, we believe that multiple zero-knowledge cryptocurrency implementations is a blessing to society. Like Zcoin, Zcash is also enabling individual freedom and open commerce to the world by increasing financial privacy. We applaud the work that the Zcash team is doing. With that in mind, it is important to understand the inherent tradeoffs between the Zerocoin and Zerocash protocols. Zcoin has some major advantages over Zcash, as well as significant disadvantages. By increasing awareness of these tradeoffs, privacy-centric users can more effectively use either coin tailored to their concerns and specific use cases.
You may also read more at our blog post.
https://zcoin.io/zcoin-and-zcash/