Aptos Turns On Encrypted Mempool, and Privacy Now Costs Extra Gas
Aptos switched on an encrypted mempool for its mainnet on Monday, letting users hide what a transaction does until the block holding it is final.
The feature is opt-in, per transaction. Your address and the fee you pay stay visible — the payload does not. Transactions are encrypted client-side with a key the validator set regenerates each epoch, and the block leader orders blocks while blind to what they do.
What stays sealed, and what does not
Only the payload is hidden: the function being called and its arguments. The sender account and gas fields stay visible, which keeps the chain auditable. Existing Move contracts need no changes, and the TypeScript SDK handles encryption from version 7.0.0 onward.
No single validator can open a pending transaction. Decryption requires the same two-thirds honest-stake majority that produces every block, so the trust assumption is the one you already accept by using the chain.
What privacy costs you
Protection is not free. Encrypted transactions must clear a minimum gas-unit price of 200 Octas, twice the network base minimum, and the SDK enforces that floor automatically. Benchmarks across 50 nodes added roughly 20 milliseconds per block. Aptos finalizes blocks in under a second, so that overhead is a small fraction of total time.
Two caveats matter here. Keyless and account-abstraction signers are not supported, and encrypted multisig is feature-gated on some networks — a build can succeed while the submission is still rejected.
How this differs from private RPCs
Gnosis Chain has run a Shutter-based encrypted mempool since July 2024, and Flashbots Protect routes transactions privately to builders. Aptos argues its version is different because its own validators handle both ordering and decryption, rather than trusting a separate committee or builder.
The proposal, AIP-144, targets over 1,000 TPS at launch using batched threshold encryption that reconstructs a whole block at constant size per validator.
Why traders should care
Petra is the first wallet to surface the option at signing, and Decibel, a perpetuals exchange on Aptos, plans to keep orders private until they execute. Confidential APT already concealed transfer data earlier this year.
For anyone trading size on-chain, the point is simple. Bots profit from seeing your order before it lands — that visibility is the entire attack. Optional encryption does not fix MEV everywhere, but it removes the cheapest way to exploit you on one chain.