Aptos has introduced an optional Encrypted Mempool feature on its mainnet, designed to keep transaction details concealed until validators finalize their order in a block. The measure targets maximal extractable value (MEV) tactics such as frontrunning and sandwich attacks, in which automated bots use information about pending transactions to trade ahead of, or around, another user’s order.
According to Cointelegraph, Aptos said the feature is intended for institutions submitting large transactions, traders seeking to reduce MEV exposure, AI agents and blockchain developers. The system is optional, meaning users can choose whether to submit an encrypted transaction rather than use the network’s existing process.
Why pending transactions are exposed to MEV
A mempool is the holding area for transactions that have been submitted to a blockchain but have not yet been included in a block. On many networks, observers can see important details while a transaction is waiting, including the assets and amounts involved, the function being called and the contracts being used.
That visibility can allow automated trading bots to identify a pending order and attempt to benefit from it. In a frontrunning transaction, a bot places its own trade ahead of the original order. A sandwich attack goes further by placing trades before and after the target transaction, seeking to profit from the price movement caused by the user’s order.
The potential cost to traders has been substantial on other networks. Cointelegraph’s analysis of EigenPhi data found that sandwich attacks cost Ethereum traders about $60 million in the 12 months through October 2025. Bitquery recorded nearly 6.9 million such attacks on Solana during an 11-month period, affecting approximately 2.2 million wallets and generating $29.7 million for bots.
How Aptos’ system handles encrypted orders
For a user who opts in, a compatible wallet or application encrypts the transaction on the user’s device before sending it to Aptos. The transaction’s assets, amounts and other contents remain hidden. The sender’s address and gas fee, however, continue to be visible.
The encrypted transaction then enters the Aptos mempool. Validators agree on where it should appear in the block without seeing its contents. Once that ordering has been finalized, the validators collectively decrypt the transaction, after which it is executed and recorded on the blockchain.
Aptos says no individual validator can decrypt a pending transaction alone. By delaying access to the transaction details until the ordering decision is complete, the system is intended to stop bots from identifying an order early enough to insert trades ahead of it or on either side of it.
The approach differs from some other MEV-protection systems. Gnosis Chain launched an encrypted mempool using Shutter in July 2024, while Ethereum’s Flashbots Protect sends transactions privately to block builders. Aptos says its own validators perform both the ordering and decryption functions, instead of depending on a separate decryption committee or trusted block builders.
Trade-offs and Aptos market picture
The protection is not free. Aptos’ developer documentation says encrypted transactions have a minimum gas price equal to twice the network’s base minimum. Aptos also reported that tests involving 50 nodes added about 20 milliseconds per block compared with its existing consensus implementation.
The feature therefore gives users a choice between the network’s standard transaction process and a more private submission method with higher minimum gas costs and a small measured delay. The launch does not mean every Aptos transaction is encrypted: users must opt in, and the wallet or application they use must support the feature.
Moneyiar market data at 09:44 on October 13, 2026, showed Aptos (APT) at $0.8371466044, down 4.81% over 24 hours but up 1.38% over seven days. At 09:43, Plasma (XPL) was $0.0817359308, down 5.77% in 24 hours and 10.85% over seven days; The Sandbox (SAND) was $0.0603662726, down 5.58% and 7.84%, respectively; and Ontology (ONT) was $0.0557020349, down 6.17% over 24 hours and 8.06% over seven days.
Aptos’ rollout adds another blockchain-level attempt to address the information advantage that bots can gain from visible pending orders. Its impact will depend on adoption by wallets, applications, institutions and traders, since the encrypted route is an opt-in feature rather than a default replacement for ordinary transactions.
