Related work

Dates are from each project’s public commit history, read on 2026-10-22.

Project	Proves	Does not prove
zreceipt	One output’s recipient, amount and memo, opened with the sender’s outgoing cipher key, for Sapling, Orchard and Ironwood. Proposed the output-disclosure text for ZIP 311 in zcash/zips#1406	Who sent the payment. Spend authority exists as a prototype test, not in the product
zcash-delivery-proof	That a transaction delivered one note (receiver, value, memo), checked with no key	Who sent it, and that it was mined
`zcash_disclosure`	Chosen outputs as Bech32m disclosures, a candidate encoding	A signature or spend authority
Viewing-key processors (BTCPay plugin, CipherPay)	Everything the key can see	Nothing is withheld

All of these stop at the part of ZIP 311 that reveals an output. Zceipt implements the part ZIP 311 says makes a disclosure complete: proof that the payer’s spend authority made the payment.

What Zceipt adds

Spend authority for Orchard and Ironwood: a fresh Action proof plus a spend-authorization signature, so a receipt can’t be made by someone who only watched the payment.
Relationships between payments: same payer, distinct payers, sibling accounts, key sets, delegation, income, threshold policy (composability). None of the projects above has any of these.
A chain check: the verifier fetches the transaction by txid, with a block hint so the server sees only a block.
A second verifier written independently in Python.

Spend authority, by date

Zceipt’ first commit on 2026-10-14 creates and verifies the spend-authority proof. zreceipt added a prototype test of a similar construction on 2026-10-20; its product discloses outputs only. The repository’s docs/RELATED-WORK.md has the full comparison and docs/COMPARISON.md compares viewing-key payment processors.

Design

Interfaces

Context

What Zceipt adds

Spend authority, by date

​What Zceipt adds

​Spend authority, by date

What Zceipt adds

Spend authority, by date