Newsletters: add 153 (2021-06-16)

Author: harding

_posts/en/newsletters/2021-06-16-newsletter.md

@@ -0,0 +1,125 @@
+---
+title: 'Bitcoin Optech Newsletter #153'
+permalink: /en/newsletters/2021/06/16/
+name: 2021-06-16-newsletter
+slug: 2021-06-16-newsletter
+type: newsletter
+layout: newsletter
+lang: en
+---
+This week's newsletter celebrates the lock-in of the taproot soft fork,
+describes a draft BIP for improving transaction
+privacy by varying the fields used to implement anti fee sniping, and
+features an article about the challenges of combining transaction
+replacement with payment batching.  Also included are our regular
+sections with announcements of new software releases and release
+candidates, plus notable changes to popular Bitcoin infrastructure
+software.
+
+## News
+
+- **🟩  Taproot locked in:** the [taproot][topic taproot] soft fork and
+  related changes specified in BIPs [340][bip340], [341][bip341], and
+  [342][bip342] were locked in by signaling miners last weekend.
+  Taproot will be safe to use after block 709,632, which is expected in
+  early or mid November.  The delay gives time for users to upgrade
+  their nodes to a release (such as Bitcoin Core 0.21.1 or later) that will
+  enforce taproot's rules, ensuring that funds received to taproot
+  scripts after block 709,632 are safe even if there's a problem with
+  miners.
+
+    Developers are encouraged to start [implementing taproot][taproot
+    uses] so they can
+    be ready to take advantage of greater efficiency, privacy, and
+    fungibility as soon as the activation is complete.
+
+    Readers celebrating the lock-in of taproot may also wish to read a
+    [short thread][wuille taproot] about taproot's origins and history by
+    developer Pieter Wuille.
+
+- **BIP proposed for wallets to set nSequence by default on taproot transactions:**
+  Chris Belcher [posted][belcher post] a draft BIP to the Bitcoin-Dev
+  mailing list suggesting an alternative way wallets can implement [anti
+  fee sniping][topic fee sniping].  The alternative method would enhance
+  the privacy and fungibility of transactions made by single-sig users,
+  [multisignature][topic multisignature] users, and users of certain
+  contract protocols such as taproot-enabled LN or advanced
+  [coinswaps][topic coinswap].
+
+    Anti fee sniping is a technique some wallets implement to discourage
+    miners from trying to steal fees from each other in a way that would
+    reduce the amount of proof of work expended on securing Bitcoin and
+    limit users' ability to rely on confirmation scores.  All wallets
+    that implement anti fee sniping today use nLockTime height locks,
+    but it's also possible to implement the same protection using
+    [BIP68][] nSequence height locks.  This wouldn't be any more
+    effective at preventing fee sniping, but it would provide a good
+    reason for regular wallets to set their nSequence values to the same
+    values that are required for transactions in certain
+    multisignature-based contract protocols, such as ideas for coinswaps
+    and taproot-enabled LN.  This helps make regular wallet transactions
+    look like contract protocol transactions and vice versa.
+
+    Belcher's proposal suggests wallets randomly choose between using
+    either nLockTime or nSequence with 50% probability when both options
+    are available.  Overall, if the proposal is implemented, it will
+    allow users of regular single-sig transactions or uncomplicated
+    multisignatures to join together with users of contract protocols to
+    mutually improve each others' privacy and fungibility.
+
+## FIXME:article
+
+FIXME:harding to rebase on #582 on Tuesday
+
+## Releases and release candidates
+
+*New releases and release candidates for popular Bitcoin infrastructure
+projects.  Please consider upgrading to new releases or helping to test
+release candidates.*
+
+- [Rust Bitcoin 0.26.2][] is the project's latest minor release.
+  Compared to the previous major version, it contains a several API
+  improvements and bug fixes.  See the [changelog][rb changelog] for
+  details.
+
+- [Rust-Lightning 0.0.98][] is a minor release containing several
+  improvements and bug fixes.  <!-- there's no release notes or
+  changelog I can see, so not much to say here. -->
+
+- [LND 0.13.0-beta.rc5][LND 0.13.0-beta] is a release candidate that
+  adds support for using a pruned Bitcoin full node, allows receiving
+  and sending payments using Atomic MultiPath ([AMP][topic multipath payments]),
+  and increases its [PSBT][topic psbt] capabilities, among other improvements
+  and bug fixes.
+
+## Notable code and documentation changes
+
+*Notable changes this week in [Bitcoin Core][bitcoin core repo],
+[C-Lightning][c-lightning repo], [Eclair][eclair repo], [LND][lnd repo],
+[Rust-Lightning][rust-lightning repo], [libsecp256k1][libsecp256k1
+repo], [Hardware Wallet Interface (HWI)][hwi repo],
+[Rust Bitcoin][rust bitcoin repo], [BTCPay Server][btcpay server repo],
+[Bitcoin Improvement Proposals (BIPs)][bips repo], and [Lightning
+BOLTs][bolts repo].*
+
+- [Bitcoin Core GUI #4][] UI external signer support (e.g. hardware wallet) FIXME:dongcarl
+
+- [Bitcoin Core #21573][] updates the version of libsecp256k1 included
+  in Bitcoin Core.  The most notable change is the use of the
+  optimized modular inverse code described in Newsletters [#136][news136
+  safegcd] and [#146][news146 safegcd].  Performance evaluations posted
+  to the PR found it accelerated old block verification by about 10%.
+
+- [C-Lightning #4591][] bech32m support FIXME: Xekyo
+
+{% include references.md %}
+{% include linkers/issues.md issues="4,21573,4591" %}
+[Rust Bitcoin 0.26.2]: https://github.com/rust-bitcoin/rust-bitcoin/releases/tag/0.26.2
+[Rust-Lightning 0.0.98]: https://github.com/rust-bitcoin/rust-lightning/releases/tag/v0.0.98
+[LND 0.13.0-beta]: https://github.com/lightningnetwork/lnd/releases/tag/v0.13.0-beta.rc5
+[belcher post]: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-June/019048.html
+[news136 safegcd]: /en/newsletters/2021/02/17/#faster-signature-operations
+[news146 safegcd]: /en/newsletters/2021/04/28/#libsecp256k1-906
+[taproot uses]: https://en.bitcoin.it/wiki/Taproot_Uses
+[wuille taproot]: https://twitter.com/pwuille/status/1403725170993336322
+[rb changelog]: https://github.com/rust-bitcoin/rust-bitcoin/blob/master/CHANGELOG.md#0262---2021-06-08

_topics/en/fee-sniping.md

@@ -37,6 +37,9 @@ optech_mentions:
   - title: "C-Lightning #3465 implements anti fee sniping for withdrawal transactions"
     url: /en/newsletters/2020/02/12/#c-lightning-3465
 
+  - title: BIP proposed for wallets to set nSequence by default on taproot transactions
+    url: /en/newsletters/2021/06/16/#bip-proposed-for-wallets-to-set-nsequence-by-default-on-taproot-transactions
+
 ## Optional.  Same format as "primary_sources" above
 # see_also:
 #   - title:

_topics/en/taproot.md

@@ -176,6 +176,9 @@ optech_mentions:
   - title: "Bitcoin Core #22051 adds support for importing descriptors for taproot outputs"
     url: /en/newsletters/2021/06/09/#bitcoin-core-22051
 
+  - title: "Taproot locked in; activation to occur at block 709,632"
+    url: /en/newsletters/2021/06/16/#taproot-locked-in
+
 ## Optional
 see_also:
   - title: MAST