NU5 and Halo Arc timeline update

Today we’re announcing an update to the anticipated timeline for NU5 and Halo Arc. This isn’t a decision we came to lightly; instead, it reflects our commitment to the safety and quality of the release, along with our commitment to ecosystem readiness. The new mainnet activation target is April 18, 2022.

NU5 is arguably the largest upgrade to the Zcash protocol since the project launched and consists of a number of significant improvements, including Unified Addresses and the first deployment of Halo on Zcash. NU5 will be an incredible milestone, implementing the first shielded pool on Zcash that no longer requires a trusted setup. Additionally, Unified Addresses and “auto-shielding” in our mobile wallet SDKs will enable Shielded by Default.

After assessing the remaining work, we’re allocating additional time for development and to focus on ecosystem outreach and preparations. Specific items include:

  • A proof of zero-knowledge and soundness for the Halo 2 construction, which, to the best of our knowledge, is the first full proof of a PLONK-based protocol and the first explicit proof written for the polynomial commitment scheme based on the inner product argument.
  • In addition to the security assessments done by NCC and QEDIT, the ECC Core and Security teams are conducting an additional internal security audit and thorough review of the Orchard circuit. In a prior internal audit, the team identified a couple of circuit bugs after the assessments were completed. This additional audit will provide further scrutiny on the circuit code and ZIP implementations for NU5.
  • We’re working hard on ecosystem readiness and to secure commitments from our partners to be ready at activation. We’re also asking that they participate in a co-marketing campaign promoting Shielded By Default. We’re already engaged with our partners and are making great progress with our miners, exchanges, and wallet vendors.

The new April activation target for NU5 will correspond with the release of the Halo Arc product suite, which includes an NU5-compatible Zcashd, an updated ECC Reference Wallet, updated mobile wallet SDKs, and features that will enable Zcash to be Shielded by Default. Full details can be found on our schedule page, which always reflects the latest information.

Although we hoped to activate NU5 and release Halo Arc earlier in the year, we are sure this additional time will allow for optimum development, review, and testing, and to ensure the community and our partners are ready for launch. We are incredibly excited about NU5 and what it means for the future of Zcash.