Bitcoin wallet protections shrink the prize unevenly Bitcoin transactions can reduce the incentive to revisit a prior block through lock fields. A wallet can set a lock so the transaction first becomes mineable in the block after the current tip, which excludes it from a replacement of the current tip.
Widespread use changes the economics of fee sniping because a miner rebuilding the earlier height loses access to some of the newest pending transactions, lowering the revenue available in its alternative block. The protection shrinks the available prize and leaves reorganization attempts technically possible.
Bitcoin Optech’s technical overview says developers see current protections as incomplete. Their effectiveness depends on which wallets and transaction-creation systems set the relevant fields, how consistently they do so, and which transaction types they cover.
BIP 326 describes anti-fee-sniping behavior for Taproot transactions through nLockTime or nSequence. It remains a draft informational proposal, and wallets can adopt the approach gradually under existing consensus rules, leaving real-world coverage dependent on implementation choices.
An open Bitcoin Core issue from April 2026 documents one concrete inconsistency. The issue says the send RPC and GUI wallet flow set nLockTime near the current block height, whereas the createrawtransaction and walletcreatefundedpsbt paths default to zero. The proposed consistency change remains open.
The difference means Bitcoin Core’s anti-fee-sniping default is applied unevenly across transaction-creation paths. Estimating the network-wide effect would require data on how much transaction volume each path represents, which the issue does not provide.
Implementation coverage therefore belongs inside the security-budget discussion because a mitigation can be technically available while its network effect depends on the share of pending transactions that use it. Broader and more consistent lock-field behavior would reduce the fees available to a miner trying to rebuild the previous height.
Miners also face a coordination problem because the return from contesting a block depends partly on whether other miners extend the accepted tip. A broad migration toward protective transaction construction changes the available reward directly and can occur under existing consensus rules, avoiding a miner-coordination requirement.
Signals to watch before the next subsidy cut The next subsidy reduction provides a useful monitoring horizon, though its security effects will depend on fee demand, fee distribution, miner behavior, propagation, and mitigation adoption.
Four signals provide a better view than aggregate revenue alone:
Adjacent-block fee gaps. Persistent or extreme gaps mark the periods when a prior block carries the largest extra prize.
Competing-block frequency. A change in same-height races shows shifting network behavior while leaving the cause open.
Immediate next-block timing. The first seconds after a high-fee block are the interval highlighted by the study.
Lock-field coverage. More consistent use across wallet and automated transaction-creation paths can reduce the revenue available in a rebuilt prior block.
Each signal captures a different part of the incentive because fee gaps describe the prize, block races and timing describe network outcomes, and lock-field use describes a defense.
Bitcoin’s fee market can produce occasional outlier blocks even while fees remain a small share of miner revenue. Those outliers deserve closer attention because mining incentives emerge in each block interval, while monthly revenue charts blur the short-lived extremes.
The post Bitcoin’s security risk starts when one block gets far more fees than the next appeared first on CryptoSlate.
https://cryptoslate.com/bitcoins-security-risk-starts-when-one-block-gets-far-more-fees-than-the-next/
August 26, 2026 1
