Zcash starts merging Tachyon scaling code into its live privacy software — but the upgrade itself is still not live

Zcash developers have released Udon, a piece of software that begins moving parts of the proposed Project Tachyon scaling upgrade into Zakura Common, the shared cryptography library used to create and verify the network's private transactions, CoinDesk reported on 29 September, citing Tachyon lead Sean Bowe.

Udon landed in Zakura Common on Monday (28 September), per Bowe. Common handles the heavy math behind shielded payments: a Zcash wallet must prove a private payment is valid without revealing sender, recipient or amount, and network nodes then verify that proof. Earlier work on Common cut proof-creation time from more than three seconds to under 200 milliseconds in some tests, CoinDesk reported in August. Zakura is jointly developed by Bowe's team and Dev Ojha's Valar Group.

The stated long-term target, attributed to Bowe and Ojha, is more than 50,000 private payments a second. At that rate, they estimate today's cryptography would force each node to take in more than 500 megabytes of data every second. Tachyon is meant to combine proofs from many payments into fewer proofs, cutting what nodes must receive and check — at the cost of more memory to build each proof, which is why the team is reusing the faster Common code.

The gap between that ambition and current usage is large. Per the report, Udon does not demonstrate Tachyon's speed; it only starts the integration. Tachyon still needs further development and a security review before any possible activation, and it has not been activated on the network.

Key facts

• Udon released into Zakura Common on Monday 28 September, moving parts of Project Tachyon into live software — Sean Bowe, via CoinDesk (29 Sept).
• Prior Common work cut proof-creation from >3 seconds to <200 ms in some tests — CoinDesk (Aug 2026).
• Long-term goal: >50,000 private payments/second; at that rate ~500 MB/second per node under current cryptography — Bowe and Ojha estimates, via CoinDesk.
• Shielded-fund transactions averaged ~11,700/day in the seven days to 21 Sept, falling to ~6,200/day in the seven days to 28 Sept — ZecStats, via CoinDesk.

The real-world read

This is an incremental engineering milestone dressed in a big number. The eye-catching "50,000 payments a second" is a stated target from the developers themselves, not a benchmark Udon achieves — the report is explicit that Udon "does not demonstrate Tachyon's speed" and that the upgrade is unactivated, unaudited and needs more work. The 500 MB/second figure is also a developer estimate of a hypothetical load, not a measured result. Meanwhile actual shielded activity is going the other way, down roughly 47% week-on-week (11,700 to 6,200 per day) by ZecStats' count — a scaling upgrade for volume that isn't currently there. Note too that this rests on a single secondary source relaying Bowe; there's no independent test data yet to check the timing claims against.

This is news coverage, not investment advice.

Sources

• CoinDesk (29 Sept 2026), "Zcash developers begin moving Tachyon code into faster private-payment software" — primary reporting on Udon's release, developer targets, and usage data; relays statements from Tachyon lead Sean Bowe and cites ZecStats for transaction figures and its own August reporting for the proof-time numbers. Secondary source; not marketing.