Zcash targets 50,000 TPS for private transactions after security scare

Zcash's new Zakura node and Project Tachyon aim to scale shielded transactions to 50,000 per second, up from roughly 20 today, as the privacy-focused blockchain pursues Visa-level throughput.

"Zcash's existing cryptography would require a node to process over 500 megabytes of data per second to match Visa-level throughput," Sean Bowe, a founding member of Zcash's zero-knowledge cryptography team and lead of Project Tachyon, said in a blog post. "The cryptography our teams are developing closes much of that gap."

The Zakura client, released July 16 as a pruned fork of the Zcash Foundation's Zebra node, cuts sync time to under two minutes by offering ready-made 11-gigabyte chain snapshots — 680 times faster than a full sync, the team said. It supports the Ironwood (NU6.3) upgrade activating July 28 at block 3,428,143, which introduces a turnstile mechanism to cap withdrawals from the Orchard shielded pool. The fix responds to a soundness bug discovered May 29 by Shielded Labs researcher Taylor Hornby that had allowed potential counterfeit ZEC creation since Orchard launched in May 2022.

The scaling push comes as ZEC trades roughly 48% below its pre-vulnerability level, according to CoinGecko data. The Ironwood turnstile traps any counterfeit coins inside the shielded pool, letting honest balances migrate out over time, but the four-year window the bug was live means the chain holds no record of whether fake ZEC was ever created — leaving the token's supply reliability dependent on the new boundary mechanism.

How Zakura and Tachyon aim to close the throughput gap

Project Tachyon, led by Bowe, tackles the core bottleneck by developing recursive proofs — a single proof that attests to the validity of thousands of others. Under this system, a node verifies one proof instead of thousands, reducing consensus data requirements from 100 megabytes per second to 500 megabytes, a level the team claims is technically achievable. Valar Group, led by Osmosis cofounder Dev Ojha, is separately working on private information retrieval techniques that let wallets fetch their own data from servers without revealing which entries were requested — removing the wallet bottleneck that currently caps shielded throughput at roughly one transaction per second.

The NU7 testnet, launched May 22, showed early progress: block times dropped from 75 seconds to 25 seconds, and shielded transaction throughput doubled compared to prior benchmarks, according to the project.

Ironwood's turnstile and the cost of a four-year-old bug

The Ironwood upgrade represents the final chapter of a vulnerability that nearly broke Zcash in June. Hornby found that the Orchard proof circuit contained a soundness flaw that let an attacker mint counterfeit ZEC with no on-chain trace. Developers disabled Orchard through an emergency response completed June 2, then restored it with a corrected circuit via the NU6.2 hard fork on June 3.

Because zero-knowledge proofs reveal nothing beyond the fact that they verified, the chain holds no record of what any Orchard transaction moved during the four-year window. The turnstile mechanism seals Orchard to new deposits, making it the only exit — any fake coins inside are trapped there. Honest balances can migrate out over time, restoring supply reliability.

The Zcash Foundation raised $25 million in March 2026, and the shielded pool now constitutes roughly 30% of total supply, according to project data. Whether that share grows or stalls will signal whether users trust the post-vulnerability protocol.

This article is for informational purposes only and does not constitute investment advice.