
A look back: NU5 and network sandblasting
This post details ECC’s motivations, challenges, and accomplishments with regard to zcashd Network Upgrade 5 (NU5) and the sandblasting attack.

This post details ECC’s motivations, challenges, and accomplishments with regard to zcashd Network Upgrade 5 (NU5) and the sandblasting attack.

NU5, the first major upgrade since November 2020, includes the launch of the Orchard shielded payment protocol, utilizing the Halo proving system to remove reliance on complex setup ceremonies.
During the course of testing NU5, a consensus bug emerged that caused the testnet chain to fork. The ECC Core team found it quickly and subsequently identified and implemented a

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.
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.

Electric Coin Co. (ECC) has entered into an agreement with Protocol Labs, the Filecoin Foundation, and the Ethereum Foundation to explore Halo R&D, including how the technology might be used in their respective ecosystems.

We’re introducing “auto-shielding” in our mobile wallet SDKs and unified addresses at the Zcash protocol level. In supporting wallets, these two features ensure your Zcash transaction and balance information is automatically encrypted — Shielded by Default — in the latest, most secure shielded pool.

NU5 will move Zcash to the Halo proving system, representing the continual evolution of our zk-SNARK technology stack. Unified addresses introduce a future-proof address format that prioritizes shielded adoption.

As the first implementation of Halo within Zcash, this would serve as a catalyst for Zcash user confidence and scalability, while making the protocol more attractive, faster and less expensive for others to build on.

The Halo 2 zero-knowledge proving system, invented and developed at Electric Coin Co. (ECC), eliminates the trusted setup, reducing the attack surface of the Zcash protocol and improving assurance about ZEC supply integrity.

For the Halo 2 project, we have designed a new cycle of elliptic curves, Pallas and Vesta, which we collectively refer to as the Pasta curves.

Last year, our team announced a collection of discoveries and research milestones as part of our Scalability 2021 mission for Zcash. Our primary result was Halo, a new zk-SNARK that
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