Silent Payments: Receiving #32966

Eunovo · 2025-07-14T08:30:35Z

This PR is part of integrating silent payments into Bitcoin Core. Status and tracking for the project is managed in #28536
This PR is based on #28201 and will remain in draft until #28201 is merged.

This PR:

Adds a Silent Payments descriptor implemenation
Adds a SilentPaymentsDescriptorScriptPubKeyMan Impl that is a subclass of DescriptorScriptPubKeyMan
Implements Silent Payments scanning for the wallet
Updates sending logic to use silent-payments destination for change when sending to silent-payments destination
Adds unit and functional tests for silent payments-related functionality

Follow-ups

Silent Payments Label functionality is incomplete in this PR and will be added as a follow-up PR.

DrahtBot · 2025-07-14T08:30:40Z

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/32966.

Reviews

See the guideline for information on the review process.
A summary of reviews will appear here.

Conflicts

Reviewers, this pull request conflicts with the following ones:

#34075 (fees: Introduce Mempool Based Fee Estimation to reduce overestimation by ismaelsadeeq)
#33874 (wallet: refactor ProcessDescriptorImport by naiyoma)
#33112 (wallet: relax external_signer flag constraints by Sjors)
#33034 (wallet: Store transactions in a separate sqlite table by achow101)
#32861 (Have createwalletdescriptor auto-detect an unused(KEY) by Sjors)
#32763 (wallet: Replace CWalletTx::mapValue and vOrderForm with explicit class members by achow101)
#31974 (Drop testnet3 by Sjors)
#31260 (scripted-diff: Type-safe settings retrieval by ryanofsky)
#30214 (refactor: Improve assumeutxo state representation by ryanofsky)
#29136 (wallet: addhdkey RPC to add just keys to wallets via new unused(KEY) descriptor by achow101)
#28333 (wallet: Construct ScriptPubKeyMans with all data rather than loaded progressively by achow101)
#27865 (wallet: Track no-longer-spendable TXOs separately by achow101)
#27260 (Enhanced error messages for invalid network prefix during address parsing. by portlandhodl)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

DrahtBot · 2025-07-14T10:32:42Z

🚧 At least one of the CI tasks failed.
_{Task tidy: https://github.com/bitcoin/bitcoin/runs/45909076324}
_{LLM reason (✨ experimental): The CI failure was caused by errors in clang-tidy checks, specifically in descriptor.cpp and walletutil.cpp, which are treated as failures due to warnings-as-errors settings.}

Hints

Try to run the tests locally, according to the documentation. However, a CI failure may still
happen due to a number of reasons, for example:

Possibly due to a silent merge conflict (the changes in this pull request being
incompatible with the current code in the target branch). If so, make sure to rebase on the latest
commit of the target branch.
A sanitizer issue, which can only be found by compiling with the sanitizer and running the
affected test.
An intermittent issue.

Leave a comment here, if you need help tracking down a confusing failure.

src/wallet/rpc/wallet.cpp

Sjors · 2025-07-14T20:13:21Z

Another thing I noticed while testing using the send RPC, in a wallet with only an sp() descriptor, is that it insists on having a bech32 descriptor for change:

Transaction needs a change address, but we can't generate it. Error: No bech32 addresses available.

It seems safer, for backups, to send change to the same silent payment address.

Wallet created by:

bitcoin rpc createwallet Silent blank=true silent_payments=true
bitcoin rpc importdescriptors '[{"desc": "sp(xprv...,xprv...)",  "timestamp": "now", "active": true]

Also looking forward to have labels back :-)

josibake

Did a big overview with @Sjors , leaving the notes from our discussion as a review. In general, I think we should investigate using a custom type for the scan key since a lot of the changes seem to be hacking around the fact we represent the scan key as a private key, but then often need to use it as not a private key.

Still in the process of reviewing, but leaving the initial notes for now

josibake · 2025-07-15T14:14:18Z

src/script/descriptor.cpp

@@ -206,6 +206,8 @@ struct PubkeyProvider
    /** Get the descriptor string form including private data (if available in arg). */
    virtual bool ToPrivateString(const SigningProvider& arg, std::string& out) const = 0;

+    virtual std::optional<std::string> ToPrivateString(const CKey& key) const = 0;


While reviewing the PR, it seems a lot of things could be simplified by if we just treated the scan key as something that isn't a CKey, i.e., we introduce a completely new object for holding the scan key. I think that would allow us to drop this commit and simplify other places where we are trying to work around the fact that a scan key isnt really a private key.

I haven't thought this all the way through yet, but in my initial pass on the PR it seems like it should be possible.

src/outputtype.cpp

src/script/descriptor.cpp

src/wallet/scriptpubkeyman.cpp

src/interfaces/chain.h

src/wallet/wallet.cpp

The scan key will be derived while the descriptor is parsed, so we must pass the master xpriv into `GenerateWalletDescriptor`. The spend key is expanded later so it is specified as an xpub and path instead.

In future commits, a Silent Payment enabled wallet will write found SIlentPaymentOutputs to the DB. Although the XOnlyPubKey can be derived from adding the Spend pubkey and the tweak, we opt to save the the found XOnlyPubKey because that removes the need for a CPubkey::TweakAdd() in the codebase

Co-authored-by: Ava Chow <[email protected]>

silent_payments wallet needs to scan entire blocks since it doesn't know ahead of time which scriptPubKeys to use in it's fast rescan filter.

Co-authored-by: Ava Chow <[email protected]>

traditionally, the receiving scripts are known to the core wallet because they are added to the addressbook at the time they are requested. in silent payments, the outputs are not known until found. its important, however, to have the found scripts in the addressbook so all of the change accounting can be down properly. this commits adds found outputs to the address book if they are not change. the way change is determined is a bit hacky in that we just check if the found output was found with a label (since this is the only label currently implemented). in the future, we should specifically check for a change specific label.

The wallet tries to match change OutputTpe to other outputs to preserve privacy. Use silent payment change address when sending coins to: - any silent payment address - any taproot address

`CreateTransaction` fails if change_type is set to OutputType::SILENT_PAYMENTS and there are no eligible inputs for the transaction. This commit modifies `CreateTransaction` logic to make a second attempt to create a tx without OutputType::SILENT_PAYMENTS change_type

This allows wallets with only sp descs to use sp change destination for transactions.

Co-authored-by: macgyver13 <[email protected]>

DrahtBot · 2025-12-16T15:36:02Z

🐙 This pull request conflicts with the target branch and needs rebase.

josibake mentioned this pull request Jul 10, 2025

BIP352 tracking issue #28536

Open

15 tasks

DrahtBot added the CI failed label Jul 14, 2025

Sjors reviewed Jul 14, 2025

View reviewed changes

src/wallet/rpc/wallet.cpp Show resolved Hide resolved

DrahtBot mentioned this pull request Jul 15, 2025

wallet: Remove wallet version and several legacy related functions #32977

Merged

josibake reviewed Jul 15, 2025

View reviewed changes

Eunovo and others added 6 commits December 1, 2025 08:04

wallet: generate sp() descriptor

57f1fa4

The scan key will be derived while the descriptor is parsed, so we must pass the master xpriv into `GenerateWalletDescriptor`. The spend key is expanded later so it is specified as an xpub and path instead.

wallet: create SilentPaymentDescriptorScriptPubKeyMan

b62f1a1

Co-authored-by: Ava Chow <[email protected]>

wallet: scan for silent payments

a2a5897

Co-authored-by: Ava Chow <[email protected]>

wallet/rpc: add create silent-payments wallet option

b3e6bfa

Co-authored-by: Ava Chow <[email protected]>

wallet: disable fast rescan for silent_payments wallet

961f6c0

silent_payments wallet needs to scan entire blocks since it doesn't know ahead of time which scriptPubKeys to use in it's fast rescan filter.

Eunovo force-pushed the 2025-implement-bip352-receiving branch from 55485a6 to fcc8b88 Compare December 1, 2025 10:00

Eunovo and others added 12 commits December 1, 2025 11:08

wallet: import silent payments descriptor

66e219d

tests: add silent payments receiving functional tests

4a921b4

Co-authored-by: Ava Chow <[email protected]>

wallet/rpc: add sp-address support to getaddressinfo

56aa363

use silent payments change when sending

c0651b9

The wallet tries to match change OutputTpe to other outputs to preserve privacy. Use silent payment change address when sending coins to: - any silent payment address - any taproot address

wallet/spend: Filter out coins not eligible to pay sp change dest

90a0b45

wallet: prefer silent_payments over Bech32m as fallback change type

39904a5

This allows wallets with only sp descs to use sp change destination for transactions.

wallet/tests: Enable Silent Payments in wallet unit tests

ccc59e2

wallet/gui: add silent_payments option to createwalletdialog

545898f

wallet/gui: add silent-payments to address type dropdown

94aafba

tests: silent-payments wallet coin control

3bfab00

Co-authored-by: macgyver13 <[email protected]>

Eunovo force-pushed the 2025-implement-bip352-receiving branch from fcc8b88 to 3bfab00 Compare December 1, 2025 10:13

DrahtBot added CI failed and removed Needs rebase CI failed labels Dec 1, 2025

DrahtBot mentioned this pull request Dec 2, 2025

wallet: refactor ProcessDescriptorImport #33874

Draft

DrahtBot mentioned this pull request Dec 16, 2025

fees: Introduce Mempool Based Fee Estimation to reduce overestimation #34075

Open

DrahtBot added the Needs rebase label Dec 16, 2025

kevkevinpal mentioned this pull request Dec 16, 2025

refactor: Improve assumeutxo state representation kevkevinpal/bitcoin#231

Closed

Eunovo mentioned this pull request Jan 9, 2026

Add "silentpayments" module implementing BIP352 (take 5, using "LabelSet" scanning approach) bitcoin-core/secp256k1#1792

Open

theStack mentioned this pull request Jan 11, 2026

Silent Payments module: discussion about different scanning approaches (BIP, LabelSet, hybrid) bitcoin-core/secp256k1#1799

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Silent Payments: Receiving #32966

Silent Payments: Receiving #32966

Eunovo commented Jul 14, 2025

Uh oh!

DrahtBot commented Jul 14, 2025 •

edited

Loading

Uh oh!

DrahtBot commented Jul 14, 2025

Uh oh!

Uh oh!

Sjors commented Jul 14, 2025 •

edited

Loading

Uh oh!

josibake left a comment

Uh oh!

josibake Jul 15, 2025

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

DrahtBot commented Dec 16, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

Silent Payments: Receiving #32966

Are you sure you want to change the base?

Silent Payments: Receiving #32966

Conversation

Eunovo commented Jul 14, 2025

Uh oh!

DrahtBot commented Jul 14, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Code Coverage & Benchmarks

Reviews

Conflicts

Uh oh!

DrahtBot commented Jul 14, 2025

Uh oh!

Uh oh!

Sjors commented Jul 14, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

josibake left a comment

Choose a reason for hiding this comment

Uh oh!

josibake Jul 15, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

DrahtBot commented Dec 16, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

DrahtBot commented Jul 14, 2025 •

edited

Loading

Sjors commented Jul 14, 2025 •

edited

Loading