Zcoin Development Update 14 Feb 2019

Zcoin Electrum Light Wallet

  • Electrum light wallet rebase to 3.3.3 is released with much better performance and stability.


  • AMD miner, sgminer fixed crashing issues and increased speed for Vega
  • Made a new release.
  • To work on optimizing cpuminer


  • Discussion on algorithm to automatically determine which mints to use to meet a private spend request.
    • Originally decided to always pick the mints that are largest so that the private spend request could be met in the smallest amount of spends. However leads to many smaller mints.
    • Better approach is for the algorithm to calculate the least amount of Zerocoin transactions needed to meet a private spend request that also takes into accounts the re-minting of change. This is because mints are future spends.
  • Testnet for Sigma to be started soon
  • Some issues with secp256k1 library resolved
  • Plan to release Sigma with core features for testing end of February


  • Academic paper being rearranged to clearly separate
    • scheme
    • claimed security properties
    • proofs of the claimed properties.
  • This will assist in third party verification of claims
  • Ongoing discussion on whether to allow shielded to shielded transactions which sacrifices element of supply auditability. Leaning towards launching Lelantus without having this feature first.
  • Exploring alternative ways to cryptographically prove ‘shielded’ supply so that forging of zk proofs alone won’t be enough to cheat system.
  • Batching of bullet proofs work is almost complete and will have working code for this portion by end of week.

Core Upgrade (Bitcoin Core 0.17)

  • Code to be pushed to public repo in a few days and open for testing


  • Incomplete shutdown issue located
  • Issue where non-existent mints are showing been fixed
  • Settings page to include slider to adjust how many percent of coins should be kept as mints after startup.
  • Found weightage issue with Zerocoin spends where it is weighted 4x the size leading to only 3 spends fitting within a transaction.
  • New release by this weekend.
  • Hierarchical deterministic (HD) minting almost working simplifying wallet backup.