Overwinter Is Here: Zcash Claims 'Successful' First Hard Fork

Zcash has successfully activated its Overwinter hard fork, setting the privacy-focused cryptocurrency up for its major Sapling upgrade in the autumn.

AccessTimeIconJun 26, 2018 at 3:00 p.m. UTC
Updated Sep 13, 2021 at 8:06 a.m. UTC

Privacy-focused cryptocurrency zcash executed its first and long-awaited hard fork on Tuesday morning.

Called Overwinter, the upgrade was activated at 00:42 UTC on June 26 – the moment the network mined block 347,500, as previously reported by CoinDesk.

The event is primarily aimed to gear up the zcash code for its massive Sapling hard fork, currently scheduled to occur in October, and includes changes including versioning, replay protection for future forks and some performance improvements.

Josh Swihart, marketing director for the Zcash Company, explained in a blog post after the fork that the "successful" event was helped by the network's first implementation of a two-tiered governance model for such upgrades.

The first tier is an optional upgrade, which aims to "remove chaos introduced by other governance models where users are forced down a certain path, potentially without their knowledge or consent," he said.

The second tier is "advocacy and education," helping node operators make "well-informed decisions" about future hard forks prior to their execution.

While it was not immediately clear how many nodes executed the Overwinter fork, zcash engineer Simon Liu previously told CoinDesk that there was "unanimous support from all parties" for the upgrades. Indeed, 12 exchanges were listed as supporting the fork on the zcash website, while other mining pools publicly expressed support for Overwinter elsewhere.

In the wake of Overwinter's activation, the Zcash Company also published a proposed two-year roadmap. Most notably, this would direct research into "privacy-by-default," Swihart wrote in a separate post.

This could see users by default using the platform's shielded "z-addresses," meaning that their balances and transactions are not visible to observers of the blockchain. Currently, the default is for unshielded "t-addresses," meaning that their transaction data is publicly on show.

Swihart expanded:

"The Zcash protocol and supporting tools, like the reference wallet, need to support broad-based privacy adoption. ... We will track and measure adoption through a number of means including the number of shielded transactions, the number of third parties supporting shielded addresses, and the number of third parties supporting shielded addresses by default."

Zcash also plans to carry out market research on the issue, including a study of global users and use cases, to "better understand both current use and identify opportunities for improvement," Swihart wrote.

Other proposed efforts include creating a reference wallet for third-parties, scalability research, business and marketing pushes, ongoing maintenance and decentralization support, according to the announcement.

Winter landscape image via Shutterstock


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