Bitcoin Optech Newsletter #429
ニュースレターでは、既存のBIPを変更せずにマルチパーティウォレットが集約DLEQ証明を用いてサイレントペイメントを作成できる新しい2ラウンドプロトコルと、古いCore Lightningバージョンで発見されたDoS脆弱性の責任ある開示、そして低複雑度脆弱性向けのBitcoin Coreの更新されたセキュリティポリシーを概説しています。さらに、通常のQ&A、リリース発表、主要なBitcoinインフラソフトウェアの変更点も含まれています。
要点
- The proposed silent‑payment protocol works with FROST and MuSig2 without changing existing BIPs.
- Security relies on an open‑question hardness assumption; formal proofs are still pending.
- Core Lightning versions 25.02‑26.04 are vulnerable to a self‑referential channel announcement DoS.
- Bitcoin Core now back‑ports fixes for easily discoverable bugs to all maintained releases.
- Operators should upgrade to CLN 26.04.1 and Bitcoin Core 32.1 to stay protected.
Silent payments for multiparty wallets
Bitcoin Optech highlights a protocol introduced by Oleksandr Kurbatov that enables silent‑payment transactions from wallets using multiparty signing schemes such as FROST and MuSig2. The design lets a coordinator collect weighted ECDH shares from each signer, then aggregate an AggDLEQ proof that satisfies BIP374. Because the proof exchange stays inside the wallet’s coordination channel, no new PSBT fields or BIP changes are required. Kurbatov notes that a paper with formal security proofs is under internal review, but the core claim—that corrupted signers and the coordinator cannot forge a proof—depends on an assumption whose hardness remains an open question.
Core Lightning denial‑of‑service vulnerability
The newsletter also details a self‑referential channel announcement bug discovered by Nishant Bansal in Core Lightning (CLN) versions 25.02 through 26.04. The software failed to enforce distinct node IDs in a channel announcement, allowing a crafted announcement to be stored on‑disk and later crash the node on every restart. Exploitation required only a funded 2‑of‑2 output and minimal on‑chain fees. The issue was responsibly disclosed, patched in CLN 26.04.1, and mirrored in BOLT 7 via requirement #1333. Operators still on vulnerable releases are urged to upgrade promptly.
Updated Bitcoin Core security policy
Antoine Poinsot announced a change to Bitcoin Core’s vulnerability handling for “easily discoverable” bugs—those that can be found with simple prompts to large language models or basic fuzzing. Instead of waiting for a major release, the project now back‑ports fixes to every maintained branch, issues point releases quickly, and publishes advisories alongside them. The three vulnerabilities referenced (Core #36665, #36667, #36669) were fixed under this new regime, causing the tagged 32.0 release to be skipped in favor of 32.1, which also brings mempool‑based fee estimation, PSBTv2 defaults, and faster block validation.