This week’s newsletter references a discussion about BIP151 encryption for the peer-to-peer network protocol, provides an update on compatibility between Bitcoin and the W3C Web Payments draft specification, and briefly describes some notable merges in popular Bitcoin infrastructure projects.

Action items

  • Allocate time to test Bitcoin Core 0.17RC3: Bitcoin Core has uploaded binaries for 0.17 Release Candidate (RC) 3. Testing is greatly appreciated and can help ensure the quality of the final release.

  • Plans for the second Optech workshop are progressing, with date and location confirmed for Paris on November 12th/13th. The tentative list of topics is:

    • Replace-by-fee vs. child-pays-for-parent as fee replacement techniques
    • Partially Signed Bitcoin Transactions (BIP 174)
    • Output script descriptors for wallet interoperability (gist)
    • Lightning wallet integration and applications for exchanges
    • Approaches to coin selection & consolidation

    Member companies who would like to send engineers to the workshop should email Optech.


  • BIP151 discussion: as mentioned in Newsletter #10, Jonas Schnelli has proposed an updated draft of BIP151 encryption for the peer-to-peer network protocol. Cryptographer Tim Ruffing provided constructive criticism of the draft on the Bitcoin-Dev mailing list this week that received also-constructive rebuttals from Schnelli and Gregory Maxwell. These posts may be interesting reads for anyone wondering why certain cryptographic choices were made in the protocol, such as the use of the NewHope quantum-computing resistant key exchange.

  • W3C Web Payments Working Group update: Lightning Network developer Christian Decker is a member of this group attempting to create standards for web-based payments. In a reply sent to the Lightning-Dev mailing list, Decker explains why he thinks the current draft specification will be fundamentally compatible with both payments to Bitcoin addresses and Lightning Network payments. The draft even explicitly allocates the XBT currency code to Bitcoin.

Notable commits

Notable commits this week in Bitcoin Core, LND, and C-lightning. Reminder: new merges to Bitcoin Core are made to its master development branch and are unlikely to become part of the upcoming 0.17 release—you’ll probably have to wait until version 0.18 in about six months from now.

  • Bitcoin Core #12775 adds support for RapidCheck (a QuickCheck reimplementation) to Bitcoin Core, providing a property-based testing suite that generates its own tests based on what programmers tell it are the properties of a function (e.g. what it accepts as input and returns as output).

  • Bitcoin Core #12490 removes the signrawtransaction RPC from the master development branch. This RPC is labeled as deprecated in the upcoming 0.17 release and users are encouraged to use the signrawtransactionwithkey RPC when they are providing their own private key for signing or the signrawtransactionwithwallet RPC when they want the built-in wallet to automatically provide the private key.

  • Bitcoin Core #14096 provides documentation for output script descriptors which are used in the new scantxoutset RPC in Bitcoin Core 0.17 and are expected to be used for other interactions with the wallet in the future.

  • LND made almost 30 merges in the past week, many of which made small enhancements or bugfixes to its autopilot facility—its ability to allow users to choose to automatically open new channels with automatically-selected peers. Several merges also updated which versions of libraries LND depends upon.

  • C-Lightning #1899 added several hundred lines of documentation to its repository this week, most of it inline code documentation or updates to files in its /doc directory.