URI-Encapsulated Payments

Note retrieval

Ideally: a lightweight wallet can receive the funds with the assistance of a more powerful node, with minimal information leakage to that node (e.g., using simple lookups queries that can be implemented via Private Information Retrieval). The open question is how to do this given that most practical PIR are for retrieving an index out of an array, not a key from a key value standpoint.

Other Questions

Should senders delay admitting a generated transaction by a random amount to prevent traffic analysis (i.e., so the messaging service operator cannot correlate messages with on-chain transactions)?

Consider the behavior in case a chain reorgs invalidates a sent payment. Should we specify a Merkle root or block hash to help detect this reason for payment failure? Or have some servers that maintain a cache of payments that were invalidated by reorgs?

References

Publication Blockers

• Clean up semantics.
• Clean up rationale.

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1. Information on BCP 14 — "RFC 2119: Key words for use in RFCs to Indicate Requirement Levels" and "RFC 8174: Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words"↩︎

2. Zcash Protocol Specification, Version 2023.4.0 or later↩︎

3. Android Developer Guides: Handling Android App Links↩︎

4. Apple Xcode Documentation: Allowing apps and websites to link to your content↩︎

5. Microsoft Universal Windows Platform Documentation: Enable apps for websites using app URI handlers↩︎

6. ZIP 321: Payment Request URIs↩︎

7. Uniform Resource Identifier (URI): Generic Syntax↩︎

8. Zcash Protocol Specification, Version 2023.4.0 or later↩︎

9. Zcash Protocol Specification, Version 2023.4.0 or later↩︎

10. Zcash Protocol Specification, Version 2023.4.0 or later↩︎

11. Zcash Protocol Specification, Version 2023.4.0 or later↩︎

12. Zcash Protocol Specification, Version 2023.4.0 or later↩︎

13. ZIP 321: Payment Request URIs↩︎

14. ZIP 321: Payment Request URIs↩︎

15. FinCEN Guidance FIN-2019-G001. May 9, 2019. Application of FinCEN’s Regulations to Certain Business Models Involving Convertible Virtual Currencies↩︎