Aptos launched its Encrypted Mempool feature on October 12, introducing optional transaction privacy on mainnet as its native APT token dropped more than 11% within 24 hours. The upgrade conceals pending transaction details until validators confirm their order, limiting opportunities for frontrunning and sandwich attacks. Aptos developed the system to protect institutional traders, individual users, automated trading agents, and decentralized applications.
The feature encrypts transaction instructions before they enter the blockchain network. As a result, validators cannot inspect hidden trading details while determining transaction order.
However, wallet addresses and network fees remain visible. Once validators finalize the ordering process, they collectively decrypt the instructions and execute the transactions.
Aptos Introduces Encrypted Transactions to Prevent MEV Attacks
The Encrypted Mempool targets maximal extractable value (MEV), which allows trading bots to exploit pending transactions for profit. Bots often monitor public transaction queues to identify large trades. Some place orders ahead of users, while others execute transactions before and after their targets.
Aptos warned that this visibility enables bots to trade against users or copy their strategies. The new system aims to limit those opportunities by concealing transaction instructions before execution. Unlike private transaction builders or external security committees, Aptos relies on its existing validator network to order and decrypt transactions.
Meanwhile, its encryption model requires cooperation from a stake-weighted majority of validators. No individual validator can independently decrypt pending transaction contents. The technology follows AIP-144, which outlines the network's encrypted transaction processing mechanism. Aptos first detailed its plans in May 2026 before bringing the technology to mainnet in October.
Encrypted Mempool Adds Gas Costs but Maintains Fast Processing
Encrypted transactions carry additional fees compared with standard network activity. According to Aptos developer documentation, users must pay at least 200 octas per gas unit. That represents twice the network's minimum base gas price. Each encrypted transaction also incurs 375 additional gas units for decryption, excluding normal execution costs.
Despite these requirements, network testing showed limited processing overhead. Aptos reported approximately 20 milliseconds of additional latency per block during tests involving 50 nodes. The tests used its production AptosBFT consensus implementation, which normally finalizes blocks in less than one second.
Before launch, cybersecurity firm ZKSecurity conducted an independent security review of the encryption system. For developers, Aptos introduced encrypted transaction support through version 7.0.0 of its TypeScript software development kit.
Existing Move smart contracts require no changes to accommodate the upgrade. Petra became the first wallet to support encryption during transaction signing. Meanwhile, decentralized perpetual futures exchange Decibel plans to conceal pending trading orders through the feature.
Read More: 10 Leading Aptos Ecosystem Tokens Ranked by Market Cap (2026)
Aptos Targets Sandwich Attacks After Millions in Trading Losses
The launch follows research documenting widespread sandwich attacks across blockchain markets. Bitquery identified approximately 6.9 million such attacks on Solana between October 30, 2025, and October 7, 2026.
Its findings linked 2,545 bot wallets to attacks involving approximately 2.2 million wallets. The activity extracted $29.7 million before trading costs. Around 96% of identified attacks involved memecoins associated with Pump.fun markets.
Daily attacks increased from approximately 3,400 in late 2025 to 51,900 in September 2026. Although the research focused on Solana, it illustrates the trading behavior Aptos seeks to restrict. Aptos maintains public auditability after execution while keeping pending instructions concealed.
The network also offers separate privacy tools, including Keyless Accounts and Confidential APT. In May, Aptos Foundation and Aptos Labs committed more than $50 million toward ecosystem development involving trading infrastructure, artificial intelligence agents, and blockchain research.
The initiative included Decibel and Shelby, which focuses on data-heavy applications. Aptos also reported that Decibel had surpassed $1 billion in cumulative trading volume during development.
Conclusion
Aptos has introduced Encrypted Mempool to protect pending transactions from frontrunning and sandwich attacks while maintaining public transaction records after execution. Although the upgrade adds gas costs, testing showed limited latency. Petra already supports the feature, while Decibel plans to adopt encrypted orders as APT faces selling pressure.