From: "'nervana21' via Bitcoin Development Mailing List" <bitcoindev@googlegroups.com>
To: "bitcoindev@googlegroups.com" <bitcoindev@googlegroups.com>
Subject: [bitcoindev] [BIP Proposal] Anti-Fee-Sniping with LockTime
Date: Tue, 18 Aug 2026 08:00:01 +0000 [thread overview]
Message-ID: <wWGWjMw9TI22vp4VzCm4xJJS3IGA1UhndMKynUkB04BqeoRjhe-QbDbJU-GMQq0nnOnXuB__u8KcdIcxU5i8Cy9pbTbtJ7Hi583FzLVojek=@pm.me> (raw)
Hello all,
Anti-fee-sniping with nLockTime has been present in Bitcoin Core since
2014 and in Electrum since 2017. BIP326 assumes this nLockTime behavior
as the baseline and uses nSequence instead for some taproot spends.
However, the nLockTime rules themselves were never specified in a BIP.
https://github.com/nervana21/bips/blob/anti-fee-snipe/bip-anti-fee-sniping-with-locktime.md
The BIP draft follows Bitcoin Core's DiscourageFeeSniping and
IsCurrentForAntiFeeSniping functions. nLockTime is set to the current tip height.
With probability 10%, a uniform random integer in 0..99 is subtracted
and the result is clamped at 0. A locktime equal to the tip height
cannot be included in a remine of the tip. An older locktime chosen on
the privacy branch can. nLockTime is set to 0 during initial block
download or when the tip is more than 8 hours old. The policy is not
applied when nLockTime is already set or when any input already has a
preset nSequence. Test vectors are included.
Constructive criticism is greatly appreciated.
Cheers,
nervana21
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next reply other threads:[~2026-08-18 9:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-18 8:00 'nervana21' via Bitcoin Development Mailing List [this message]
2026-08-19 13:31 ` [bitcoindev] Re: [BIP Proposal] Anti-Fee-Sniping with LockTime b10c
2026-08-21 20:29 ` 'nervana21' via Bitcoin Development Mailing List
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