Feature Request: BIP351 Private Payments Support

[privatepayments]

Private Payments (BIP351) is a stealth address system for Bitcoin that allows the user to post a static code and receive payments to a separate address space for each sender.

There are multiple use cases for Private Payments, but the static donation code seems to be the most compelling. A user wishing so solicit donations from the public may safely associate a payment code with her identity and receive funds in a relatively private manner.

The user story is similar to BIP47:

• Receiver posts their payment code
• Sender creates a notification payload and either posts it to the chain as an OP_RETURN or to some other bulletin board system
• Receiver scans the chain for these notification payloads and upon finding one, generates the chain of stealth addresses

Improvements over BIP47:

• Supports multiple address types
• Better notification payload privacy
• Smaller notification payloads

For more context, check out privatepayments.org and the Rust reference implementation.

[clarkmoody]

After the merge of #5373 adding BIP47 support, most of the infrastructure is in place for BIP351.

cc @abhiShandy

[Overtorment]

i actually would like to see a formal spec for silent payments to compare, before choosing one or the other
(silent payments formal BIP is not written yet, is it?)

[Overtorment]

summon @RubenSomsen

[RubenSomsen]

@Overtorment We have a BIP draft that will be published soon for public review. Feel free to dm me for an early link.