ECC Engineering: Year in Review

ECC Engineering is a small, global organization focused on building and supporting technology to provide people with access to a fair and open currency — regardless of location or demographic. In short, our mission is to empower everyone with economic freedom. In 2021, we continued to make tremendous progress in both R&D and engineering, which we feel will benefit Zcash for years to come. 

ECC actively develops and maintains the Zcashd consensus client, the official reference implementation of the Zcash Protocol Specification. The Zcashd client allows you to send and receive ZEC, mine ZEC, and verify transactions. It is in use by mining pools and exchanges all over the world.

ECC also develops and maintains the Zcash iOS and Android software development kits (SDKs), the ECC reference wallets for iOS and Android, and lightwalletd, a backend service that provides a bandwidth-efficient interface to the Zcash blockchain.

Since 2016, ECC has been at the forefront of groundbreaking research and development with implications beyond the cryptocurrency world. Zcash was the first project to successfully implement zero-knowledge proofs, and ECC has established a reputation for shipping quality, production-ready code at regular intervals. We release new versions of Zcashd on roughly six-week release cycles and have historically performed an average of one or two network upgrades (or “hard forks”) per year.

Historical and future release and network upgrade information can always be found on our schedule page.


We had many successes in 2021 across all of our engineering-related teams including Core, Mobile, and DevSecOps, a team comprising what was previously the separate DevInfra and Security teams. These successes included the regular cadence of releases as well as breakthrough cryptographic research, developments to move the shielded wallet ecosystem forward, operational enhancements and advancements, and a continued demonstration of our commitment to security best practices, ensuring safe and secure releases and network upgrades. 

Halo on Zcash

Our focus in 2021 was primarily on our upcoming network upgrade, NU5, the largest network upgrade in Zcash history. We had hoped to activate NU5 in 2021, but elected to delay the activation to meet our historic standards for safety and quality, and to allow plenty of time for ecosystem partner testing and integration. NU5 brings Halo to Zcash in the embodiment of the Orchard Shielded Protocol, along with numerous other improvements, including unified addresses, a future-proof address format. Halo eliminates the need for a trusted setup and is a foundational piece of our scalability initiative, enabling options such as transaction and block aggregation, the latter being the cornerstone of succinct blockchains. 

The Filecoin, Ethereum, and ECC collaboration

In September, we announced a multi-faceted collaboration and research agreement with Protocol Labs, the Filecoin Foundation, and the Ethereum Foundation around Halo 2, including how the technology might be used in their respective ecosystems. The collaboration accelerates the development of recursion in Halo 2 and explores options for the integration of Halo 2 into the Filecoin and Ethereum ecosystems.

Proof of stake and interop research

There’s strong public signaling in support of Zcash moving to proof of stake and a growing demand for standardized interop touchpoints to enable innovation on top of Zcash. We began early market and technical research into proof-of-stake protocols and interop platforms that could potentially be options for Zcash in the future.

Other highlights include:

  • Released seven versions of Zcashd and successfully activated our sixth network upgrade, NU5, on testnet.
  • Published an update to the Network Upgrade Pipeline (NUP), establishing a more agile process that still retains the safeguards inherent in the NUP while making it easier for protocol teams outside of ECC and the Zcash Foundation to participate.
  • Reduced Initial Block Download (IBD) data by more than 90% by eliminating redundant block header requests and replies.
  • Published ECC’s proposed feature set for NU5 including the Orchard Shielded Protocol and unified addresses
  • Formed a Scientific Advisory Group to help guide the scientific evolution of the Zcash protocol 
  • Designed and introduced unified addresses, a future-proof Zcash address format that improves usability, increases the ease of interoperability, and supports shielding Zcash by default.
  • Established a responsible disclosure process with key wallet partners, NightHawk and Unstoppable, for vulnerabilities found in our mobile SDKs and reference wallet apps.
  • Conducted a study of decentralized markets on the Zcash blockchain that involves multiple assets, in support of our Zcash Shielded Asset (ZSA) research
  • Added auto-shielding to the ECC Wallet SDKs, a UX feature that automatically moves funds from a transparent address to a shielded address and a component of our Shielded by Default initiative.
  • Activated NU5 on testnet aimed at enabling existing Zcash users to test their software and make the necessary changes to be compatible with the new consensus rules.
  • Completed and published the NU5 specification and implementation security assessments which were conducted by QEDIT and NCC.  

For a full recap of 2021, including all our engineering activity, please browse our Electric Coin Co. blog.

Wishing you the best for a healthy, happy, and successful 2022!

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