Newsletters: add 240 (2023-03-01)

Author: harding

_posts/en/newsletters/2023-03-01-newsletter.md

@@ -0,0 +1,121 @@
+---
+title: 'Bitcoin Optech Newsletter #240'
+permalink: /en/newsletters/2023/03/01/
+name: 2023-03-01-newsletter
+slug: 2023-03-01-newsletter
+type: newsletter
+layout: newsletter
+lang: en
+---
+This week's newsletter summarizes a discussion about the fastest way to
+verify that a BIP32 master seed backup probably hasn't been corrupted
+without using any digital devices.  Also included are our regular
+sections with announcements of new releases and release candidates, plus
+summaries of notable changes to popular Bitcoin infrastructure software.
+
+## News
+
+- **Faster seed backup checksums:** Peter Todd [replied][todd codex32]
+  to the discussion about a draft BIP for Codex32 (see [last week's
+  newsletter][news239 codex32]), a scheme that allows creating,
+  verifying, and using recovery codes for a [BIP32][topic bip32] seed.
+  A particular advantage of Codex32 over existing schemes is the ability
+  to verify the integrity of backups using just pen, paper,
+  documentation, and a modest amount of time.
+
+    As designed, Codex32 provides very strong assurances about its
+    ability to detect errors in the backups.  Peter Todd suggested a far
+    easier method would be to generate recovery codes that could have
+    their parts added together to produce a checksum.  If dividing the
+    checksum by a known constant produced no remainder, it would verify
+    the integrity of the backup within the parameters of the checksum
+    algorithm.  Peter Todd suggested using an algorithm that provided
+    roughly 99.9% protection against any typos, which he thought would
+    be sufficiently strong, easy for people to use, and easy for people
+    to memorize so that they didn't need the extra Codex32 materials.
+
+    Russell O'Connor [replied][o'connor codex32] that a full Codex32
+    recovery code can be checked much faster than full verification if
+    the user is willing to accept less protection.  Checking just two
+    characters at a time would guarantee detection of any
+    single-character mistake in a recovery code and provide 99.9%
+    protection against other substitution errors.  The process would be
+    somewhat similar to generating the type of checksum that Peter Todd
+    described, although it would require using a special lookup table
+    which ordinary users would be unlikely to memorize.  If verifiers
+    were willing to use a different lookup table each time they checked
+    their code, each additional verification would increase their chance
+    of detecting an error up until the seventh verification, where they
+    would have the same assurance as they would receive from performing
+    full Codex32 verification.  No changes are required to Codex32 to
+    obtain the reinforcing quick check property, although Codex32's
+    documentation will need to be updated to provide the necessary
+    tables and worksheets in order to make it usable.
+
+## 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.*
+
+- [HWI 2.2.1][] is a maintenance release of this application for
+  allowing software wallets to interface with hardware signing devices.
+
+- [Core Lightning 23.02rc3][] is a release candidate for a new
+  maintenance version of this popular LN implementation.
+
+- [lnd v0.16.0-beta.rc1][] is a release candidate for a new major
+  version of this popular LN implementation.
+
+## Notable code and documentation changes
+
+*Notable changes this week in [Bitcoin Core][bitcoin core repo], [Core
+Lightning][core lightning repo], [Eclair][eclair repo], [LDK][ldk repo],
+[LND][lnd repo], [libsecp256k1][libsecp256k1 repo], [Hardware Wallet
+Interface (HWI)][hwi repo], [Rust Bitcoin][rust bitcoin repo], [BTCPay
+Server][btcpay server repo], [BDK][bdk repo], [Bitcoin Improvement
+Proposals (BIPs)][bips repo], and [Lightning BOLTs][bolts repo].*
+
+- [Bitcoin Core #25943][] rpc: Add a parameter to sendrawtransaction which sets a maximum value for unspendable outputs. FIXME:glozow
+
+- [Bitcoin Core #26595][] wallet: be able to specify a wallet name and passphrase to migratewallet FIXME:bitschmidty
+
+- [Bitcoin Core #27068][] updates how Bitcoin Core handles passphrase
+  entry.  Previously, a passphrase containing an ASCII null character
+  (0x00) would be accepted---but only the part of the string up to the
+  first null character would be used in the process of encrypting the
+  wallet.  This could lead to a wallet having a much less secure
+  passphrase than the user expected.  This PR will use the entire passphrase,
+  including null characters, for encryption and decryption.  If the user
+  enters a passphrase containing null characters which fails to decrypt
+  an existing wallet, indicating they may have set a passphrase under
+  the old behavior, they'll be provided with instructions for a
+  workaround.
+
+- [LDK #1988][] adds limits for peer connections and unfunded channels
+  to prevent denial of service resource exhaustion attacks.  The new
+  limits are:
+
+    - A maximum of 250 data-sharing peers which don't have a funded
+      channel with the local node.
+
+    - A maximum of 50 peers which may currently be trying to open a
+      channel with the local node.
+
+    - A maximum of 4 channels that have not yet been funded from a
+      single peer.
+
+- [LDK #1977][] makes public its structures for serializing and parsing
+  [offers][topic offers] as defined in [draft BOLT12][bolts #798].  LDK
+  doesn't yet have support for [blinded paths][topic rv routing], so it
+  can't currently send or receive offers directly, but this PR allows
+  developers to begin experimenting with them.
+
+{% include references.md %}
+{% include linkers/issues.md v=2 issues="25943,26595,27068,1988,1977,798" %}
+[core lightning 23.02rc3]: https://github.com/ElementsProject/lightning/releases/tag/v23.02rc3
+[lnd v0.16.0-beta.rc1]: https://github.com/lightningnetwork/lnd/releases/tag/v0.16.0-beta.rc1
+[hwi 2.2.1]: https://github.com/bitcoin-core/HWI/releases/tag/2.2.1
+[news239 codex32]: /en/newsletters/2023/02/22/#proposed-bip-for-codex32-seed-encoding-scheme
+[todd codex32]: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2023-February/021498.html
+[o'connor codex32]: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2023-February/021504.html

_topics/en/hd-key-generation.md

@@ -78,6 +78,8 @@ optech_mentions:
   - title: BIP proposed to allow multiple BIP32 derivation paths in a descriptor
     url: /en/newsletters/2022/08/03/#multiple-derivation-path-descriptors
 
+  - title: Faster offline verification of BIP32 master seed backups
+    url: /en/newsletters/2023/03/01/#faster-seed-backup-checksums
 
 ## Optional.  Same format as "primary_sources" above
 # see_also:

_topics/en/offers.md

@@ -83,6 +83,9 @@ optech_mentions:
   - title: "Eclair #2479 adds support for paying offers"
     url: /en/newsletters/2023/02/22/#eclair-2479
 
+  - title: "LDK #1977 allows serializing and deserializing offers"
+    url: /en/newsletters/2023/03/01/#ldk-1977
+
 ## Optional.  Same format as "primary_sources" above
 # see_also:
 #   - title: