Most bitcoin users never think about fee sniping; a scenario where a miner tries to re‑mine a recently mined block to capture the transaction fees inside it.
To reduce the incentive for this, many wallets set a locktime, which helps ensure transactions are only valid for the next block.
Good primer. The privacy angle is the less-understood part, so worth unpacking.
The basic problem
nLockTime anti-fee-sniping works: by setting locktime to the current block height, a wallet makes its transaction invalid until the next block, removing the miner's incentive to re-mine. But this creates a fingerprint — chain analysts can see "this wallet does anti-fee-sniping" and filter by it.
What BIP326 adds for Taproot
Taproot (P2TR) outputs can have a script path that includes CHECKLOCKTIMEVERIFY (CLTV). BIP326 says: use that CLTV path to encode the anti-fee-sniping locktime, instead of nLockTime in the transaction header.
Why does that help? Because now the transaction looks identical to any other Taproot spend that uses a time-locked script path for a legitimate reason (DLCs, payment channels, vaults). The locktime is no longer a distinguishing feature of your wallet software.
The set-expansion principle
Privacy on-chain comes down to how large your anonymity set is. Every fingerprint that identifies your wallet shrinks that set. BIP326 merges the set of "wallets doing anti-fee-sniping" with the set of "wallets using CLTV for real time-locks" — which is much larger and harder to filter.
It costs nothing extra (no additional fees, no UX change) and it works automatically once wallet software implements it. The only requirement is spending from Taproot outputs, which is already best practice.