Some development updates:
Poramin has just pushed in our private repo the fixes needed to implement the Zerocoin improvements and fixes.
Tim Ruffing has pushed the the fixes on libzerocoin as well.
Tim is now looking through Poramin's code to ensure it works as intended and Aizensou and SN are working to integrate the Zerocoin improvements into the new core upgrade 0.13.
There will be an academic paper published as well to detail these fixes so that other Zerocoin implementations (if there are any other original implementations) can fix them independently and contribute to Zerocoin research.
Our new Zerocoin code will be open sourced in due time but may not be done immediately.
We are still weighing our options here as a lot of hard work and resources was put into this and all these fixes are backend which are not quite visible to the user but are important to improving the Zerocoin protocol and its security.
No Open Source ?
Can you expand on this , it's too serious to be mentioned lightly
There was some debate as to whether to allow other coins to immediately take advantage of the improvements we are making to Zerocoin and we know there are a quite a few coins out there just waiting for us to release this. Hence we were thinking maybe to delay the open sourcing by a few months and this would be balanced as the academic paper detailing these fixes would allow others to be aware of the issues and just not the code to immediately implement it. These type of steps aren't unprecedented as coins such as Dash initially closed source their Dark Send feature and NEM still has its NIS infrastructure remain closed source despite commitments to open source it.
However after discussion our team remains committed to open source and the changes we do to Zerocoin will be available when the new code goes live. We remember that without Bitcoin's open source and the researchers' work in coding the initial libzerocoin, there will be no Zcoin. So no need to worry about it, the releases we make will be all open sourced and subject to public audit/scrutiny.