EIP-8105 outlines universal encrypted mempool for Ethereum

EIP-8105 is a draft proposal for an encrypted mempool on Ethereum that would add a key-provider registry, two new transaction types and a timed decryption process designed to limit maximum extractable value from public mempool sandwich attacks.

Under the draft, accounts could register as decryption key providers in a new execution-layer system contract. Transactions would be sent as encrypted envelopes that include a small public payload — an envelope nonce, gas parameters, a key provider ID, a key ID and a signature — while the transaction’s sensitive payload remains encrypted. Blocks would accept these envelopes even though their payloads stay hidden.

The proposal defines two new EIP-2718 transaction types: 0x05 for encrypted envelopes and 0x06 for decrypted transactions. After a builder publishes an execution payload, the registered key providers referenced by the envelopes would either publish the decryption key or issue a withhold notice on a timed schedule. A Payload Timeliness Committee would monitor that publication, validate revealed keys and attest whether a valid key was available or missing.

If a decryption key is published and decryption succeeds, the decrypted transaction would execute in the following block. If a key is missing, withheld or decryption fails, the envelope would remain in the chain but its payload would be skipped; the transaction fee would still be paid. The draft enforces a strict block ordering rule: decrypted transactions at the start of a block, plaintext transactions in the middle and encrypted envelopes at the end. That order is intended to prevent insertion of value-extracting transactions between decryption and execution.

EIP-8105 is scheme-agnostic and would support multiple encryption approaches, including threshold encryption, multiparty computation committees, trusted execution environments, delay encryption and homomorphic techniques. The key provider registry would let any account register, associate keys with transactions and control when decryption material is revealed. The proposal also allows key providers to designate trusted peers and orders transactions using a key-provider trust graph to limit opportunities for selective disclosure.

The draft notes that some MEV exposure would persist because early key providers could selectively reveal or withhold keys for later transactions. The registry and trust-graph features are intended to reduce incentives and opportunities for that behavior.

Encrypted mempools have been discussed in the Ethereum community for years. Public mempool sandwich attacks are estimated to cost users roughly $60 million per year. EIP-8105 remains an open draft and is not currently a leading candidate for the first 2027 hard fork, though its concepts continue to influence ongoing design work. If elements of the proposal are adopted, developers would need new tooling for block builders, validators and key providers, and governance and security work would be required to certify registry entries and manage trust assumptions.