Due to the unforeseen vulnerabilities of the libzerocoin earlier this year, we had to halt zPIV minting in order to prevent out-of-spec inflation. Now, in preparation for the possibility that the libzerocoin does not get fixed by the original or global cryptographers, research for the next privacy protocol to replace the current Zerocoin implementation is ongoing by the PIVX core development team. As much as we would like to announce something more specific right now, this area is not something we can afford to act on in haste.
One potential option for the short-mid-term is the new advanced privacy protocol (no code name yet) that PIVX core developers have been developing in-house since 2018 based on Jonathan Bootle and Mary Maller’s research. This in-development protocol utilizes a new cryptographic accumulator, range proofs, and allows for a trust-less setup. Range proofs used will be the Bulletproofs that we developed and released late last year. However, this protocol still needs a lot of work along with a thorough review of its cryptography before it could even be considered as a viable option. We hope to hear more on this from our core developers sometime after v4.0.0 is released near end of Q3 2019. For now, the recent FAQ posted still stands.
Meanwhile, all other privacy protocols currently known in the market will also be thoroughly reviewed to determine our best options for the long term future of PIVX. There has been some great discussions and suggestions made in the PIVX Discord’s #next-privacy-protocol-chat channel and our developers are keeping a close eye on what is being said there. So all things are being considered and we hope to have a core-developer-written technical update / opinion piece on this major topic sometime in the near future.