Add experimental silent payment transaction creation support by nymius · Pull Request #220 · bitcoindevkit/bdk-cli

nymius · 2025-09-10T19:39:09Z

Description

This PR adds experimental support for creating silent payment transactions through a new CreateSpTx command. The implementation integrates the bdk_sp crate to enable sending Bitcoin to silent payment addresses.

Key changes:

Adds bdk_sp dependency as an optional feature
Implements CreateSpTx command with support for silent payment recipients
Includes parser for silent payment address:amount pairs
Returns signed transactions ready for broadcast (not PSBTs due to silent payment derivation constraints)

Notes to the reviewers

This feature is marked as EXPERIMENTAL and includes warnings against mainnet use
The command returns signed transactions directly rather than PSBTs because silent payment script pubkey derivation cannot be performed securely in a trustless manner with standard PSBT workflows
RBF is disabled for silent payment transactions (sequence set to MAX)
The implementation handles both single key and extended key signers
Error handling uses temporary .expect() calls that should be addressed in future iterations

Changelog notice

Added: Experimental silent payment transaction creation via CreateSpTx command (feature-gated behind sp flag)

Checklists

All Submissions

I've signed all my commits
I followed the conventional commit guidelines
I ran cargo fmt, clippy and test before committing

New Features

* [ ] I've added tests for the new feature

I've added docs for the new feature

tvpeter

Thank you for working on adding this feature @nymius,

I couldn't test because I don't know how to construct sp recipients. I will check the documentation on the library and will come back to test it. In the meantime, I have left some comments.
Thank you

src/handlers.rs

src/utils.rs

src/commands.rs

tvpeter

Thank you for working on this feature @nymius

I left a few comments.

Pls remember to rebase too.

src/error.rs

tvpeter · 2026-02-04T21:33:32Z

src/handlers.rs

+                if send_all {
+                    tx_builder.drain_wallet().drain_to(recipients[0].0.clone());
+                } else {


Is it possible to drain to an SP address? if so, it will be great to cover that as well.

Yes, there are different cases for this though:

CreateSpTx receives only a SilentPaymentCode to drain funds.

CreateSpTx is called with the --send_all flag and multiple SilentPaymentCode or other addresses to drain funds.

CreateSpTx is called with the --send_all flag, no SilentPaymentCode, and a plain address.

I've implemented this contemplating 1 and 3 as successful cases, and any variant of 2 as an error.

tvpeter · 2026-02-04T23:14:26Z

src/handlers.rs

+            for psbt_input in psbt.inputs.iter_mut() {
+                psbt_input.final_script_sig = None;
+                psbt_input.final_script_witness = None;
+            }


Won't it be ideal to check if they were actually finalized before resetting?

It shouldn't be necessary, as we are not passing a PSBT around, and the wallet always has all the keys required to sign, but is not difficult to implement. Above, Wallet::sign returns a boolean that indicates if the transaction was finalized or not, so I can check that.

sdmg15

tested ACK.

Script to use to reproduce

export NETWORK=regtest
export EXT_DESCRIPTOR='wpkh(tprv8ZgxMBicQKsPdMzWj9KHvoExKJDqfZFuT5D8o9XVZ3wfyUcnPNPJKncq5df8kpDWnMxoKbGrpS44VawHG17ZSwTkdhEtVRzSYXd14vDYXKw/0/*)'
export INT_DESCRIPTOR='wpkh(tprv8ZgxMBicQKsPdMzWj9KHvoExKJDqfZFuT5D8o9XVZ3wfyUcnPNPJKncq5df8kpDWnMxoKbGrpS44VawHG17ZSwTkdhEtVRzSYXd14vDYXKw/1/*)'
export DATABASE_TYPE="sqlite"
export CLIENT_TYPE="rpc"
export SERVER_URL="http://127.0.0.1:18443"
export COOKIE="/home/user/.bitcoin/regtest/.cookie"
export SP_RECIPIENT="sprt1qqdu4udd7wz7flf89m27teqzp8gxzvgpg3xudw89c0ce0f0pe0gwz6qkc4d7dg587w9rkaa0cj8rf3c28z0g45tgn0t7fzkk4s867w3eugga03ret"

raw_tx=$(cargo run -- wallet create_sp_tx --to-sp $SP_RECIPIENT:1000 | jq -r '.raw_tx' | tr -d '\n')
cargo run --features rpc -- wallet broadcast --tx $raw_tx

sdmg15 · 2026-03-16T11:22:23Z

src/handlers.rs

+            let _resigned = wallet.sign(&mut psbt, SignOptions::default())?;

+            let raw_tx = psbt.extract_tx()?;
+            if cli_opts.pretty {


Here to actually make this "pretty", there's is this shorten function that can be used. I'm not though convinced if that's helpful for users wanting to copy the full raw tx maybe they should just not use the pretty format.

Good point, I'm not sure about the use cases of the pretty flag, but I'm against shortening the transaction.

nymius · 2026-03-18T19:34:03Z

I've addressed the pending comments:

Checked the finalization status of the PSBT after the signing phase before silent payment output derivation.
Implemented logic to handle the drain to silent payment case.

I've also:

Changed the feature flag sp to silent-payments for more clarity.
Squashed all commits into a single one.

codecov · 2026-03-18T19:36:21Z

Codecov Report

❌ Patch coverage is 0% with 187 lines in your changes missing coverage. Please review.
✅ Project coverage is 10.39%. Comparing base (af0d98e) to head (beaca7e).
⚠️ Report is 9 commits behind head on master.

Files with missing lines	Patch %	Lines
src/handlers.rs	0.00%	171 Missing ⚠️
src/utils.rs	0.00%	16 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #220      +/-   ##
==========================================
- Coverage   11.16%   10.39%   -0.77%     
==========================================
  Files           8        8              
  Lines        2482     2665     +183     
==========================================
  Hits          277      277              
- Misses       2205     2388     +183

Flag	Coverage Δ
rust	`10.39% <0.00%> (-0.77%)`	⬇️

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- Adds CreateSpTx command to create transactions with silent payment outputs: this command creates signed transactions directly rather than PSBTs due to current limitations in secure shared derivation. It supports mixed recipients: regular addresses + silent payments. It DOES NOT support RBF for the created transactions. It generates signed transactions ready for broadcasting. - Adds SilentPaymentCode command to create silent payment codes from public keys and network: the silent payment code generated is independent from any of the other stateful features of bdk-cli. This command is mainly intended for experimental use, do not lock any funds to the generated code if you don't know what you are doing and don't have the keys matching the public keys used. - Adds bdk_sp dependency with "silent-payments" feature flag. - Adds silent payment recipient parsing utility. - Add README section for new silent payment commands. Note: This is experimental functionality for testing only, not recommended for mainnet use.

github-project-automation bot added this to BDK-CLI Sep 10, 2025

nymius requested review from notmandatory and tvpeter and removed request for notmandatory September 10, 2025 19:39

nymius force-pushed the feat/sp-psbt-send branch from e0a13af to bc40b76 Compare September 11, 2025 12:09

tvpeter requested changes Oct 11, 2025

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nymius force-pushed the feat/sp-psbt-send branch from bc40b76 to 8d15df7 Compare November 4, 2025 14:12

nymius requested a review from tvpeter November 4, 2025 14:12

tvpeter reviewed Feb 4, 2026

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tvpeter assigned nymius Feb 23, 2026

tvpeter moved this to In Progress in BDK-CLI Feb 23, 2026

sdmg15 reviewed Mar 16, 2026

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nymius force-pushed the feat/sp-psbt-send branch from 8d15df7 to 8290461 Compare March 18, 2026 19:22

nymius force-pushed the feat/sp-psbt-send branch from 8290461 to d297c8e Compare March 19, 2026 22:15

nymius force-pushed the feat/sp-psbt-send branch from d297c8e to beaca7e Compare March 19, 2026 22:25

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nymius commented Sep 10, 2025 •

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