Zcash Developers Propose 20-Second Blocks After NU7

Zcash targets faster payment confirmations

NU7 went live at its scheduled activation block, 3,543,405, at 02:34 UTC on November 6, according to the ZecStats tracker. The upgrade cut the target from 75 to 25 seconds under ZIP 218. The new proposal would shorten the interval by a further 20% and raise the expected number of blocks per hour from 144 to 180.

A first confirmation arrives when a miner includes the payment in a block that becomes part of the chain. Blocks can arrive sooner or later than the target, and an exchange can wait for several confirmations before crediting a deposit. An exchange that measures safety by elapsed time or accumulated mining work can retain that policy, the authors said.

The same distinction applies to cross-chain trades. The authors pointed to Zcash swaps through NEAR Intents, where a market maker may wait for a Zcash confirmation before acting. The proposal could shorten that part of the trade. It leaves other steps, including settlement on the destination chain, to the services and networks that handle them.

Shielded wallet limits would fall per block

The draft specification would cut the shared budget for shielded activity, which includes private transfers, from 330 to 264 units per block. The reduction is proportional to the shorter block interval. At the new target pace, the chain would have 25% more blocks to fit that activity into each hour.

Light wallets scan blockchain data to find private payments sent to them. The developers say that keeping the existing limits per block would raise the maximum amount of shielded activity these wallets must scan in a day by 25%. Cutting the limits per block holds that work roughly steady. Wallets would still see more block headers, the short records that identify each block.

The draft retains the two-megabyte cap on each block. It would also reduce the subsidy miners receive per block by one fifth and lengthen the halving interval from 5.04 million to 6.3 million blocks. That would preserve the expected pace of new issuance and the approximate time between halvings.

Mining tests inform the NU7.1 decision

When miners find blocks close together, part of the network can hear about one block while other nodes hear about a rival block first. The block that loses that race can end up outside the accepted chain. A shorter interval gives miners less time to receive each new block before another is found.

Ojha and Forbes reported a 1.9% rate of those orphaned blocks in a test using only Zakura node software and 3.3% in a test split between Zakura and Zebra Ándale. They ran the tests with 80 miners distributed across 12 regions and filled the blocks to two megabytes. They compared those results with the 4.68% measured in an earlier experiment used to assess the 25-second target. All three figures describe test conditions.

The community’s published schedule calls for coinholder and community-panel polling from November 16 through November 30 on development funding. Organizers said NU7.1 could carry smaller changes if engineering teams conclude they can ship them safely. The block-time draft has yet to secure a place in the upgrade.

Alternative.me’s Crypto Fear & Greed Index read 29 on November 9, up from 28 a day earlier and still in the Fear range.

The next step for the 20-second proposal is a decision on whether to put it to the community. The developers have yet to publish an activation date.