feat: add NuTachyon support to forked librustzcash crates by S1nus · Pull Request #178 · zakura-core/common

S1nus · 2026-08-24T18:07:13Z

Motivation

Add experimental NuTachyon support to the forked librustzcash crates used by
Zakura. This includes ZIP-233-compatible V7 transactions containing Tachyon
bundles and the V4 history-tree format needed to commit to Tachyon state.

Overview

Adds a cfg-gated zcash_tachyon::TachyonBundle to transaction data, using
TachyonBundle::NoBundle to represent absence.
Makes V7 follow V6's ZIP-233 header format when the NU7 configuration and
zip-233 feature are enabled.
Includes Tachyon bundle serialization, value balance accounting,
transaction IDs, signature hashes, and authorization digests.
Pins cross-implementation serialization vectors generated by Zakura for
empty, Adjunct, single-action Proven, and multi-action Proven V7 bundles.
Forks zcash_history as zakura-history and adds cfg-gated NuTachyon V4
history nodes, including Tachyon anchors and transaction counts.
Adds the new crate to workspace CI, maintenance, documentation, and package
metadata.

All experimental Tachyon behavior is gated by
zcash_unstable="nutachyon". ZIP-233 support additionally uses the existing
zcash_unstable="nu7" configuration and zip-233 feature.

Follow-up Work

The transaction builder currently initializes Tachyon bundles to
TachyonBundle::NoBundle. V7 transactions with Tachyon bundles can be
constructed without the builder; builder support will be added separately.
Complete the required supply-chain audits for the git-sourced Tachyon stack
and the new history dependencies.

Dependencies

Uses zcash/librustzcash main,
pinned at c7235b1fc4b4296b8af2e26bf2f6adb24f873f56. The Tachyon bundle and V4
history changes not yet present upstream are maintained in this repository's
forks.
zakura-core/zakura#795
pins this PR and adds the node-side NuTachyon and V7 support.

Validation

cargo +1.91.0 test -p zakura-history --all-features --locked
NuTachyon-gated zakura-history tests on Rust 1.91.0
NU7+NuTachyon-gated zakura-primitives tests on Rust 1.97.1
NuTachyon-only zakura-primitives tests on Rust 1.97.1, including exact Zakura V7 serialization vectors
Focused Clippy with warnings denied for both changed crates
zakura-history no-std build for thumbv7em-none-eabihf
Formatting, Markdown lint, and changelog policy checks

# Conflicts: # Cargo.lock

socket-security · 2026-09-01T05:10:03Z

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	cargo/primitive-types@0.12.2
	cargo/zcash_encoding@0.5.0

View full report

TalDerei

left some observations that need to be fixed.

TalDerei · 2026-09-02T22:39:26Z

+/// V4 node metadata.
+///
+/// This extends the NU6.3 history node format with metadata for the Tachyon
+/// shielded pool. Tachyon has no note commitment tree; its pool state is a
+/// running anchor, so the anchor takes the place a tree root has for the other
+/// pools.
+#[cfg(zcash_unstable = "nutachyon")]
+#[derive(Debug, Clone, Default)]
+#[cfg_attr(test, derive(PartialEq, Eq))]
+pub struct V4 {
+    /// The V3 node data retained in V4.
+    pub v3: V3,
+    /// Tachyon anchor at the start of this node's interval.
+    pub start_tachyon_anchor: [u8; 32],
+    /// Tachyon anchor at the end of this node's interval.
+    pub end_tachyon_anchor: [u8; 32],
+    /// Number of transactions containing a Tachyon bundle.
+    pub tachyon_tx: u64,
+}


I know this copies V3's structure, but something came to mind when thinking about the tachyon_tx field that sources back to a previous zebra review tachyon-zcash/zebra#32 (comment).

This PR documents bundle presence and zakura-core/zakura#795 calculates bundle presence. For Ironwood, a present bundle implies at least one action

common/crates/orchard/src/bundle.rs

Lines 438 to 443 in 69d1bc6

/// A bundle of actions to be applied to the ledger.

#[derive(Clone)]

pub struct Bundle<T: Authorization, V> {

/// The list of actions that make up this bundle.

actions: NonEmpty<Action<T::SpendAuth>>,

/// Orchard-specific transaction-level flags for this bundle.

but we're breaking that equivalence by allowing a bundle with zero actions. I don't know if that's the right decision or how deeply this decision is grounded in our proof tree? cc @turbocrime

this still hasn't been addressed and is an open question, but shouldn't block PR. can we put a todo comment?

can we rebase over main and exercise CI now that zakura-core/zakura#903?

TalDerei · 2026-09-02T23:01:00Z

+    pub tachyon_tx: u64,
+}
+
+#[cfg(zcash_unstable = "nutachyon")]


so there's a coverage gap in CI. experimental nutachyon requires MSRV 1.97 (since it's inheriting downstream configs as a cfg-gated zcash_tachyon) so it doesn't build zakura-primitives with that configuration in CI since that crate requires MSRV 1.91.

we should ideally bump MSRV for entire common, but we can just have a separate CI job that builds and tests the tachyon enabled zakura-primitives using rust 1.97.

Bumping it seems better

…nto-nutachyon # Conflicts: # Cargo.toml

…nto-nutachyon # Conflicts: # Cargo.lock # Cargo.toml

TalDerei

another round

TalDerei · 2026-09-10T03:35:39Z

+/// V4 node metadata.
+///
+/// This extends the NU6.3 history node format with metadata for the Tachyon
+/// shielded pool. Tachyon has no note commitment tree; its pool state is a
+/// running anchor, so the anchor takes the place a tree root has for the other
+/// pools.
+#[cfg(zcash_unstable = "nutachyon")]
+#[derive(Debug, Clone, Default)]
+#[cfg_attr(test, derive(PartialEq, Eq))]
+pub struct V4 {
+    /// The V3 node data retained in V4.
+    pub v3: V3,
+    /// Tachyon anchor at the start of this node's interval.
+    pub start_tachyon_anchor: [u8; 32],
+    /// Tachyon anchor at the end of this node's interval.
+    pub end_tachyon_anchor: [u8; 32],
+    /// Number of transactions containing a Tachyon bundle.
+    pub tachyon_tx: u64,
+}


this still hasn't been addressed and is an open question, but shouldn't block PR. can we put a todo comment?

TalDerei · 2026-09-10T03:37:36Z

+/// V4 node metadata.
+///
+/// This extends the NU6.3 history node format with metadata for the Tachyon
+/// shielded pool. Tachyon has no note commitment tree; its pool state is a
+/// running anchor, so the anchor takes the place a tree root has for the other
+/// pools.
+#[cfg(zcash_unstable = "nutachyon")]
+#[derive(Debug, Clone, Default)]
+#[cfg_attr(test, derive(PartialEq, Eq))]
+pub struct V4 {
+    /// The V3 node data retained in V4.
+    pub v3: V3,
+    /// Tachyon anchor at the start of this node's interval.
+    pub start_tachyon_anchor: [u8; 32],
+    /// Tachyon anchor at the end of this node's interval.
+    pub end_tachyon_anchor: [u8; 32],
+    /// Number of transactions containing a Tachyon bundle.
+    pub tachyon_tx: u64,
+}


can we rebase over main and exercise CI now that zakura-core/zakura#903?

S1nus mentioned this pull request Aug 24, 2026

feat: add NuTachyon and V7 transactions zakura-core/zakura#795

Draft

S1nus marked this pull request as ready for review August 24, 2026 18:31

S1nus force-pushed the c/nu-tachyon branch from 0899ae9 to 8221c86 Compare August 28, 2026 23:34

S1nus changed the title ~~feat: add NuTachyon librustzcash forks~~ feat: add V7 support to forked librustzcash crates Aug 28, 2026

S1nus added rust Pull requests that update rust code dependencies Pull requests that update a dependency file labels Aug 28, 2026

S1nus force-pushed the c/nu-tachyon branch from 8221c86 to 596f530 Compare August 28, 2026 23:37

S1nus added 5 commits August 31, 2026 12:41

feat: adopt upstream NuTachyon primitives

774fe2f

build: update librustzcash dependency pin

0568704

ci: satisfy changelog and source policies

fb3853e

feat(zcash_primitives): add Tachyon bundles to V7

d9d0fbf

ci: allow gated Tachyon dependency sources

f8b09aa

S1nus force-pushed the c/nu-tachyon branch from d616eac to f8b09aa Compare August 31, 2026 16:43

build: refresh Tachyon dependency lockfile

07950b0

S1nus mentioned this pull request Aug 31, 2026

feat: add NuTachyon network upgrade and V7 transaction format #254

Closed

S1nus added 4 commits August 31, 2026 14:57

build: update Tachyon dependency

a22713f

feat: fork zcash_history with NuTachyon support

7ea249e

docs: add fork provenance and changelog metadata

c8ba618

Merge pull request #297 into #178

72c8379

# Conflicts: # Cargo.lock

S1nus changed the title ~~feat: add V7 support to forked librustzcash crates~~ feat: add NuTachyon support to forked librustzcash crates Sep 1, 2026

S1nus mentioned this pull request Sep 1, 2026

feat: fork zcash_history with NuTachyon support #297

Closed

S1nus added 2 commits September 1, 2026 01:16

ci: allow zcash_encoding version split

a9daee7

build: align librustzcash dependencies with main

69d1bc6

TalDerei self-requested a review September 2, 2026 11:34

TalDerei requested changes Sep 2, 2026

View reviewed changes

S1nus added 4 commits September 3, 2026 23:56

refactor(zcash_primitives): store Tachyon wire state directly

a5e07ba

feat(zcash_primitives): support ZIP-233 in V7

1d468b8

test(zcash_primitives): add V7 serialization vectors

2873e2a

Merge remote-tracking branch 'origin/main' into codex/merge-history-i…

312f566

…nto-nutachyon # Conflicts: # Cargo.toml

S1nus added 2 commits September 4, 2026 18:02

Fix lockfile after merging common 1.1.0

8847323

Merge remote-tracking branch 'origin/main' into codex/merge-history-i…

14fc5c9

…nto-nutachyon # Conflicts: # Cargo.lock # Cargo.toml

TalDerei reviewed Sep 10, 2026

View reviewed changes

Navigation Menu

Uh oh!

feat: add NuTachyon support to forked librustzcash crates - #178

feat: add NuTachyon support to forked librustzcash crates#178
S1nus wants to merge 18 commits into
mainfrom
c/nu-tachyon

S1nus commented Aug 24, 2026 •

edited

Loading

Uh oh!

socket-security Bot commented Sep 1, 2026 •

edited

Loading

Uh oh!

TalDerei left a comment

Uh oh!

Uh oh!

TalDerei Sep 2, 2026 •

edited

Loading

Uh oh!

TalDerei Sep 10, 2026

Uh oh!

TalDerei Sep 10, 2026

Uh oh!

Uh oh!

Uh oh!

Uh oh!

TalDerei Sep 2, 2026

Uh oh!

S1nus Sep 2, 2026

Uh oh!

Uh oh!

TalDerei left a comment

Uh oh!

TalDerei Sep 10, 2026

Uh oh!

TalDerei Sep 10, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

	/// A bundle of actions to be applied to the ledger.
	#[derive(Clone)]
	pub struct Bundle<T: Authorization, V> {
	/// The list of actions that make up this bundle.
	actions: NonEmpty<Action<T::SpendAuth>>,
	/// Orchard-specific transaction-level flags for this bundle.

Uh oh!

Conversation

S1nus commented Aug 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Motivation

Overview

Follow-up Work

Dependencies

Validation

Uh oh!

socket-security Bot commented Sep 1, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

TalDerei left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

TalDerei Sep 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

TalDerei Sep 10, 2026

Choose a reason for hiding this comment

Uh oh!

TalDerei Sep 10, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

TalDerei Sep 2, 2026

Choose a reason for hiding this comment

Uh oh!

S1nus Sep 2, 2026

Choose a reason for hiding this comment

Uh oh!

Uh oh!

TalDerei left a comment

Choose a reason for hiding this comment

Uh oh!

TalDerei Sep 10, 2026

Choose a reason for hiding this comment

Uh oh!

TalDerei Sep 10, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

S1nus commented Aug 24, 2026 •

edited

Loading

socket-security Bot commented Sep 1, 2026 •

edited

Loading

TalDerei Sep 2, 2026 •

edited

Loading