Zcoin Development Update 23 August 2019

Contents

Sigma

Released 13.8.4 that fixes a Znode deadlock and some rare bugs with Sigma.
Previous release 13.8.3 also updated TOR, fixed some memory leaks and minor bugs.
Bulk of work for Sigma is complete, refactoring work to be revisited after core upgrade completion.
Decent take up for Sigma with over 84k XZC that have been minted.
Exploring companies for external audit of Sigma and possible request for donations for this as current budget is lean. Reached out to other projects who are using Sigma who may be interested in contributing.

First beta release made of new GUI. We welcome feedback in our forums!
Shoutout to Sproxet for doing a whole ton of work that made the GUI usable and massive refactoring work, that greatly improved performance.
Still missing Znode starting support, console, mint auto denomination breakdown and advanced features like coin control
To gradually phase out QT GUI wallet once full functionality is replicated onto new GUI.

Payment codes allow a single address to be shared publicly but without allowing outsiders to see payments made to it.
Has certain advantages over stealth addresses in that it can be supported by light wallets and also payments to payment codes are indistinguishable from regular payments.
Development is about 30% in progress with expected completion in about a month.
Some technical hurdles to be overcome in using Daniel Krawisz’s incomplete C++ library due to dependencies.
Development is still being done on QT GUI for the moment but will need porting work for new GUI.

Lelantus+ paper that improves proving time at the cost of increased proof sizes and slightly increased verification time has completed security proofs. To distribute to friendly researchers first before publishing.
Informal discussion with Sarang Noether from Monero Research Labs on possibility of opening up our cryptographic libraries for review/comment.
Research has changed focus from from scaling Lelantus anonymity sets into solving the requirement to ‘self-spend’ after receiving a direct anonymous transaction. Doing this greatly improves Lelantus usability and also makes it likely to be implemented in Monero (although in a different way).
- Zcash’s approach in solving the self-spend issue cannot be applied to us as they use a general arithmetic circuit zk proof to do this and neither do any of the ring signature models.
Decision not to rush Lelantus implementation but to take the time for review.

Team of 3 people has been formed with a rough road map to make Sigma enabled mobile wallet.
To work together with core team to develop the backend functionality required to communicate Sigma anonymity sets.
Edge wallet still prime candidate to be used as a base. Shout out to Paul Puey for his time.
Estimated time for completion is around 4 months but a lot of possible unforeseen hurdles.
Work done can be used for Lelantus mobile as well.

Aiming for testnet to be setup soon with the new client.
Nodes need to be re-setup when deterministic masternodes to come into play as we also don’t have any sporks features for centralization reasons. Queue reset.
To provide at least 1.5 months for hard fork notification.
Core upgrade contains RBF and CPFP but to disable such functionality for the moment as it is not required at this level of adoption and may open up DoS vectors with Dandelion.

Further work on MTP miners to be paused due to other development priorities and a relatively well optimized miner
djm34 to finish up sgminer stability fixes that were applied to ccminer.
Preliminary discussion on researching into possible RandomX parameters and feasibility. No commitment to implement.