Aptos Introduces Encrypted Mempool Feature to Combat MEV Exploits and Sandwich Attacks
The Aptos blockchain network has introduced an opt-in encrypted mempool feature on its mainnet designed to shield users from MEV-related exploits including sandwich attacks and frontrunning.
The Aptos Layer-1 blockchain network has introduced an optional new capability designed to safeguard traders against maximal extractable value (MEV) exploits, such as sandwich attacks and frontrunning.
Aptos announced on Monday that its Encrypted Mempool capability has gone live on the mainnet, giving users the choice to encrypt their pending transactions until the block ordering process is completed. According to Aptos, the feature targets institutions conducting large-scale transactions on the network, traders seeking protection from MEV exposure, AI agents, and developers.
"When you send a transaction on any major chain today, anyone watching the network can see the details before it executes, the function you're calling, the assets and amounts involved, and the contracts you're interacting with," Aptos said. "Bots use that visibility to trade against you or copy your strategy."
According to Cointelegraph's examination of EigenPhi data, sandwich attacks—a particular type of MEV exploit—resulted in approximately $60 million in losses for Ethereum traders during the 12 months ending in October 2025. Meanwhile, on the Solana network, sandwich attacks yielded $29.7 million in profits for bots during an 11-month timeframe analyzed by Bitquery, which documented almost 6.9 million attacks impacting roughly 2.2 million wallets.
How Encrypted Mempool works
Upon opting into the system, a user's compatible wallet or application encrypts the transaction details directly on their device prior to transmission to Aptos. Information including the assets and amounts in question remains concealed, though the sender's address and gas fee continue to be publicly viewable.
The encrypted transaction then joins the mempool, the holding area where pending transactions await inclusion in a block. Validators reach consensus on transaction ordering without access to the actual contents of those transactions.
After the ordering process is complete, validators work together to decrypt the transactions, which then proceed to execution and onchain recording. Individual validators lack the capability to decrypt a pending transaction independently.
By maintaining transaction details in an encrypted state until their ordering has been determined, the system can thwart bots from viewing pending orders and placing their own trades before or around them to extract value from users.
However, this protective measure involves additional expenses and introduces a minor latency increase. Based on Aptos' developer documentation, encrypted transactions require a minimum gas price set at double the network's baseline minimum. Additionally, Aptos reported that testing with 50 nodes showed the system introduces approximately 20 milliseconds of delay per block when compared to the current consensus implementation.
Aptos becomes part of a growing list of networks providing defenses against detrimental MEV. In July 2024, Gnosis Chain deployed an encrypted mempool utilizing Shutter technology, and Ethereum's Flashbots Protect service channels transactions privately to block builders. According to Aptos, what sets its approach apart is that its current validators manage both the transaction ordering and decryption processes, eliminating the need for a separate decryption committee or dependence on trusted builders.