Layer-1 blockchain Aptos has rolled out an optional new feature designed to safeguard traders, institutions, and automated systems from predatory practices associated with maximal extractable value (MEV), including frontrunning and sandwich attacks.
The network announced that its long-awaited Encrypted Mempool feature is now officially live on its mainnet. The functionality allows users to voluntarily opt in to keep their pending transactions entirely encrypted until the block ordering process has been completely finalized. According to the development team behind the protocol, the new layer of protection was specifically engineered to cater to institutions executing large-volume transactions, everyday traders seeking shelter from MEV exploitation, builders, and emerging autonomous artificial intelligence agents operating on-chain.
The fundamental vulnerability stems from how traditional public blockchains operate. When a user submits a transaction on virtually any major network today, anyone monitoring the decentralized network can inspect the details before the transaction is actually executed by the validator nodes. This transparent window reveals critical operational data, including the specific function being called, the exact digital assets and financial amounts involved, and the underlying smart contracts being interacted with. Malicious actors and opportunistic automated trading bots exploit this public visibility to intercept the data stream, trading directly against the user or copying their proprietary trading strategies for illicit profit.
The financial toll of these exploits across the broader cryptocurrency ecosystem is substantial. Sandwich attacks—a prevalent form of MEV where a bot detects a pending large transaction, purchases the same asset ahead of time to drive up the price, and then immediately sells it afterward for a guaranteed profit—cost Ethereum traders approximately $60 million over the twelve-month period leading up to October 2025, according to industry research and data analysis. The situation is similarly severe on other high-throughput networks. On Solana, sandwich attacks successfully generated roughly $29.7 million in illicit profits for automated bots over an eleven-month examination period conducted by blockchain analytics firms, which identified nearly 6.9 million distinct attacks impacting approximately 2.2 million unique user wallets.
How Encrypted Mempool Works
Under the newly deployed architecture, when a user chooses to opt in, a compatible Web3 wallet or decentralized application encrypts the contents of the transaction directly on the user’s local device prior to broadcasting it across the Aptos network. Sensitive parameters, such as the specific assets being traded and the exact monetary amounts involved, remain completely obscured from public view. Meanwhile, necessary administrative metadata, including the sender’s public wallet address and the designated gas fee, remain visible to ensure proper routing and network validation.
Once encrypted, the transaction enters the network mempool, which serves as the digital holding area where pending transactions wait to be selected and grouped into a new block. During this phase, network validators reach consensus on the chronological order of the incoming transactions while remaining entirely blind to the actual operational contents hidden inside them.
Once the precise block ordering has been definitively established and locked in, the validators collectively decrypt the transactions. The payloads are then executed sequentially and recorded permanently on the ledger. The cryptographic design ensures that no single validator can independently decrypt a pending transaction on its own, preserving decentralization and trustlessness.
Keeping transaction details strictly hidden until their execution sequence is permanently fixed effectively prevents malicious bots from reading pending orders in real-time. Without the ability to inspect the payload, bots can no longer insert their own trades ahead of or around user orders to siphon value at the expense of everyday traders and institutional participants.
This heightened security posture does, however, come with operational trade-offs involving minor financial costs and slight processing delays. According to official developer documentation provided by Aptos, encrypted transactions carry a mandatory minimum gas price set at twice the network’s standard base minimum. Furthermore, performance benchmarks released by the project indicate that the cryptographic overhead adds roughly 20 milliseconds per block during tests involving fifty active nodes, representing a minimal impact compared to the network’s existing consensus implementation.
Aptos now joins a select group of alternative blockchain networks actively deploying infrastructure to combat harmful MEV extraction. Gnosis Chain introduced an encrypted mempool utilizing threshold encryption technology in mid-2024, while Ethereum ecosystems frequently rely on private transaction routers like Flashbots Protect to route user orders directly to trusted block builders away from the public eye. Aptos highlights that its distinct architectural advantage lies in the fact that its native validators handle both transaction ordering and decryption natively, eliminating the need to rely on a separate external decryption committee or specialized trusted builders.
