Wallet Guide
The Zcash wallet layer: keys, transactions, and light-client synchronisation

Abstract

Assuming the cryptographic primitives of the Crypto Guide, the best-chain model of the Consensus Guide, and the Orchard protocol of the Ironwood Guide, this volume of The Zcash Arboretum documents the deployed wallet layer above them: hierarchical key derivation (ZIP-32), diversified and unified addresses (ZIP-316), the conventional fee (ZIP-317), the transaction-construction pipeline of librustzcash, partially created transactions (PCZT), the transaction lifecycle from broadcast through expiry (ZIP-203), payment requests (ZIP-321), and light-client synchronisation. The synchronisation chapters cover the compact-block format (ZIP-307) and its deployed divergences, the light-client service surface as lightwalletd, Zaino, and Zebra implement it, the scanning pipeline of librustzcash with its verify-first reorg discipline, commitment-tree synchronisation, and what the server learns. Every derived quantity carries its exact derivation.

The compact-block wire format is deployed but underspecified; where the draft ZIP and the deployed implementations disagree, this volume documents the deployment and flags the divergence. The protocol target is draft NU7, whose ZIP 259 leaves both activation heights unassigned as of 23 September 2026. Proposed rules and implementation-specific behaviour are distinguished where they affect the construction.