Aptos has launched an encrypted mempool on its mainnet, introducing an optional feature designed to protect transactions from frontrunning and sandwich attacks. The network announced the rollout on October 12, with Petra becoming the first wallet to offer encryption within its signing flow.
A mempool is the waiting area for transactions before they are included in a block. When transaction details are readable at this stage, attackers can use that information to trade ahead of other users. Aptos’s accepted proposal, AIP-144, describes encrypting those details before submission and revealing them only after consensus has fixed the block’s contents.
Why this matters for traders
Imagine placing a token swap. A bot that sees the pending purchase can try to buy first, pushing the price up, and sell after your trade. Your purchase ends up between the bot’s two transactions—a sandwich attack that can leave you with a worse execution price.
Keeping the pending transaction’s contents encrypted removes the advance visibility that this kind of attack relies on. The feature targets harmful forms of maximal extractable value, or MEV: value captured by exploiting transaction ordering.
How Aptos’s encrypted mempool works
For an encrypted transaction, the wallet or application encrypts the payload before sending it to the network. Validators agree on the ordering while the payload remains hidden, then collectively decrypt it before execution. A single validator cannot independently read the protected pending payload.
The system uses the network’s own validators for decryption rather than handing that role to a separate committee. Encryption remains a choice for each transaction; ordinary transactions continue to be supported.
What users can access
According to Aptos, Petra exposes an encryption option during signing. Perpetual futures exchange Decibel plans to use the feature to keep orders private until execution. Developers can integrate it using Aptos’s TypeScript SDK version 7.0.0 or later, without changing existing Move contracts.
The protection has clear boundaries. Sender addresses and gas-fee fields remain visible, and transaction data becomes public on-chain afterward. This is temporary confidentiality for pending transaction contents, rather than permanent transaction privacy.
For traders, the intended benefit is reducing the opportunity for others to act on their orders before execution. The launch announcement does not provide measured results showing how much losses from these attacks have fallen.
Source: Aptos
