Key Takeaways
Zebra: Version 7.1.0-alpha.0 introduces significant mining performance improvements, faster block processing, improved synchronization, and new monitoring capabilities.
Zodl: NU7-related librustzcash releases are complete, while Zallet Beta 4 introduces NU7 support alongside wallet recovery improvements.
Zcash Shielded Assets: QEDIT has opened two upstream Orchard PRs, completed Orchard test vectors, and made substantial progress on librustzcash integration.
Crosslink: Development continues with regular FeatureNet releases and networking improvements targeting up to 16× faster synchronization once BFT is activated.
Dynamic Fees: ZIP 2009 recommends a 1,000-zatoshi marginal fee, with additional work underway on fee estimation and transaction-priority options.
Zero Indexer: Shielded Labs’ privacy-focused light-wallet infrastructure is being tested by Zec.rocks, with Noir Wallet planning an integration.
Formal Verification: A collaborative effort to formally verify the Zcash protocol was proposed, potentially incorporating AI-assisted verification tools.
Project Tachyon: Core protocol components are being prepared for audits, an internal testnet is operational, and two draft ZIPs have been written.
Project Epoch: Shielded Labs is researching post-quantum cryptography, targeting a production-ready implementation by the end of 2027.
Eryx: Research into cryptographic timing attacks is examining sensitive operations in librustzcash and potential gaps in Zcash’s light-wallet security model.
Zebra: Mining Performance & Synchronization
Zebra 7.1.0-alpha.0 introduces several improvements aimed at making Zcash mining infrastructure faster and more responsive.
One significant change is how block templates are generated. Previously, template updates could wait for a five-second timer. Zebra can now rebuild templates immediately after mempool changes, allowing miners to respond more quickly to new transactions.
Block validation has also been optimized to reuse previously verified transactions, reducing redundant cryptographic work.
Miners can now receive coinbase-only work before a newly received block finishes validation, potentially reducing delays in preparing new mining jobs.
Additional improvements include:
Faster block verification and propagation.
Earlier block announcements to peers.
JSON-RPC 1.0 batch compatibility.
Optional ZMQ
hashblocknotifications through a custom build.New mining performance metrics.
Faster checkpoint processing and synchronization.
Zebra also reduces peer communication delays and improves overall block-processing efficiency.
Zebra 7.1.0-alpha.0 is an alpha release intended for testing, rather than a general production upgrade.
Zodl: NU7 Libraries & Zallet Beta 4
Zodl reported progress across its core Zcash libraries following NU7.
NU7-related releases across the librustzcash crates have been completed, providing updated components for wallets and other applications building on the Zcash protocol.
Zallet Beta 4 has also been released with NU7 support.
Additional work includes fixes related to recovering and spending funds from legacy zcashd wallet.dat files, continued development around ZIP 2009, and reviews of governance-related ZIPs.
Community contributions to Zallet remain welcome as development continues.
QEDIT: Zcash Shielded Assets
QEDIT reported substantial progress toward completing the implementation of Zcash Shielded Assets (ZSAs).
Two upstream Orchard pull requests are now open. One contains the full Orchard changes required for Ironwood ZSA support, while the other separates the circuit changes to make review easier.
A draft ZIP covering ZSA transaction formats and transaction digests has also been prepared.
Several implementation milestones have been reached:
Orchard test vectors: Completed.
librustzcash implementation: Largely complete.
Related test vectors: Approaching completion.
Zebra integration: Still outstanding.
QEDIT is inviting community review and feedback as the remaining integration work progresses.
The discussion also covered ZIP 248 and broader transaction-format changes intended to reduce disruption during future protocol upgrades.
Crosslink: Development & Faster Synchronization
Shielded Labs continues to advance Crosslink, with improvements to both development coordination and protocol implementation.
A new engineer with expertise in applied cryptography and zero-knowledge systems has joined the effort.
Crosslink development has also adopted a weekly release cadence, supported by public GitHub milestones and improved issue tracking.
Consensus fixes are being deployed through regular FeatureNet upgrades, allowing participants to test changes as development progresses.
One major area of work is synchronization performance.
Crosslink is preparing networking changes that would interleave the synchronization of Proof-of-Work blocks and trailing finality certificates.
Once Byzantine Fault Tolerance (BFT) is activated, this approach could deliver up to 16× faster synchronization.
The changes also aim to ensure nodes prioritize finalized chains over competing forks that have not achieved finality.
Version 17 was targeted for release, with the networking improvements planned for version 18.
Dynamic Transaction Fees
Development of Zcash’s dynamic fee infrastructure continues around ZIP 2009, which recommends a marginal transaction fee of 1,000 zatoshis.
Beyond the proposed fee parameters, work is underway on a fee estimator to help wallets determine appropriate transaction fees.
Developers are also exploring agent-based modeling to simulate how different users and market participants might respond to dynamic fee policies.
Wallet developers are encouraged to support faster transaction options and shorter transaction expiry heights, giving users more flexibility when submitting transactions.
Zero Indexer: Improving Light-Wallet Privacy
Shielded Labs highlighted progress on Zero Indexer, a privacy-focused infrastructure component designed to provide an alternative to conventional lightwalletd-based services.
The technology uses Trusted Execution Environments (TEEs) to strengthen privacy protections when wallets interact with blockchain indexing infrastructure.
An experimental deployment is already running through Zec.rocks, while Noir Wallet plans to integrate the technology into an upcoming release.
The initiative aims to reduce privacy risks associated with wallet synchronization and interactions with potentially untrusted infrastructure.
Formal Verification of the Zcash Protocol
A broader discussion explored the possibility of formally verifying the entire Zcash protocol.
Mark proposed a collaborative effort that could bring together researchers and developers to investigate whether modern formal verification techniques, potentially supported by AI-assisted tooling, could establish stronger mathematical assurances about protocol correctness.
The proposal remains exploratory, but it reflects growing interest in extending formal verification beyond individual cryptographic components.
Interested researchers and developers were invited to participate.
Project Tachyon: Preparing for Audits
Project Tachyon continues progressing toward external security review.
Core protocol and cryptographic components are being prepared for audits, while an internal testnet is already operational using mock proofs.
Drafts of two ZIPs defining the Tachyon shielded protocol have also been prepared.
Although the specifications are not yet public, the developers expect to share them with the community soon.
These milestones represent progress toward validating the protocol design before broader testing and deployment.
Project Epoch: Post-Quantum Security
Shielded Labs is exploring Zcash’s long-term cryptographic security through Project Epoch, a research effort focused on post-quantum cryptography.
The project is evaluating cryptographic constructions that could help protect Zcash against future threats from quantum computing.
Current research priorities include:
Evaluating post-quantum cryptographic constructions.
Targeting at least 128-bit security.
Formally verifying critical cryptographic components.
Assessing security and performance trade-offs.
Exploring compatibility with Project Tachyon.
The stated goal is to develop a production-ready cryptographic implementation by the end of 2027 that could support a future Zcash network upgrade.
The research effort is also expanding.
Ulrich highlighted contributions from researchers with experience at Aztec, including Luke Edwards and Suyash Bagat.
Rather than committing prematurely to a particular cryptographic approach, the researchers are evaluating competing designs and their trade-offs.
A clearer research direction is expected over the coming weeks.
Eryx: Cryptographic Timing-Attack Security
Eryx presented its Zcash Community Grant work investigating potential timing vulnerabilities in librustzcash and its dependencies.
Timing attacks exploit differences in how long sensitive operations take to execute, potentially revealing information that should remain private.
The project’s objective is not to make every operation constant-time. Instead, it aims to identify, document, classify, and test security-sensitive code paths where execution-time differences could expose confidential information.
The research considers several attacker models, including:
Network observers.
Processes running on the same device.
CPU-cache observers.
Compromised light-wallet servers.
Malicious signing coordinators.
Priority areas include wallet scanning, trial decryption, nullifier matching, transaction signing, and other operations involving sensitive information.
Revisiting Light-Wallet Security Assumptions
The presentation also prompted a broader discussion about Zcash’s security model.
Daira emphasized that timing attacks do not necessarily require attacker-controlled inputs, challenging assumptions that can influence how such vulnerabilities are evaluated.
She also questioned whether the existing light-wallet security model adequately captures certain privacy vulnerabilities.
The discussion highlighted the importance of clearer security definitions and stronger protections for long-term cryptographic secrets.
Looking Ahead
The November 12 Arborist Call highlighted development across both Zcash’s current infrastructure and its longer-term cryptographic roadmap.
Zebra continues to improve mining efficiency and synchronization, while Zodl and QEDIT advance wallet infrastructure and Zcash Shielded Assets integration.
Crosslink is working toward faster synchronization and stronger finality infrastructure, while dynamic fee development and Zero Indexer aim to improve transaction efficiency and network privacy.
Further ahead, Project Tachyon is preparing for audits, Project Epoch is evaluating post-quantum cryptography, and Eryx is investigating timing-attack risks in security-sensitive code.
Together, these efforts reflect continued work to improve Zcash’s performance, security, privacy, and scalability.
The next Zcash Arborist Call is scheduled for December 10, 2026, at 15:00 UTC.
For more information, visit the Zcash Arborist website.