Developers of Ethereum have put forth a new version of the deposit contract designed for signatures that can withstand quantum attacks.
Currently, validators connect to the network via a smart contract that accepts deposits and relies solely on BLS cryptography. The draft's authors aim to make this mechanism independent of specific schemes, allowing the blockchain to transition to other algorithms, including post-quantum ones, without the need for infrastructural changes in the future.
To achieve this, a flexible format is proposed: public keys and additional metadata will be accepted as variable-length fields, and the cryptographic scheme in use will be identified by a unique numerical code. The current BLS standard will be assigned the identifier Scheme 0.
The document does not specify a concrete post-quantum implementation; rather, it lays the groundwork for future adoption.
Additionally, developers suggest modifying the handling of deposits. Instead of the currently used Merkle tree, data is expected to be sent to the consensus level through execution requests using the EIP-7685 mechanism.
The draft also allows for a gradual phasing out of BLS: support for new deposits using this scheme can be activated during a transitional period before being completely disabled.
Post-Quantum Account Protection in Monad
Developers of the EVM-compatible protocol Monad have proposed a similar model at the account level. Initiative founders Kushal Babel and Jan Kameniš aim to separate a wallet's permanent address from the data that users employ to verify their control.
A new MIP has been published: Flexible and Upgradeable Account Authentication
Accounts can change their keys without changing their address
This lets accounts upgrade to quantum-resistant schemeshttps://t.co/Ajhnr3zwST
— Monad (@monad) August 24, 2026
In the current model, losing a private key results in loss of access to funds. Transitioning to a new security scheme requires creating a new address and transferring all assets to it.
In the proposed Monad system, a single address can utilize different authentication methods over time: it can add, change, or delete keys, connect multiple signers, and incorporate post-quantum algorithms.
The mechanism allows for configuration and recovery of access. For instance, a regular key will remain primary, but two pre-defined trusted participants can collaborate to establish a new key should the owner lose the old one. Similarly, an account can be transformed into a multi-signature without creating a new address.
This development will also enable a gradual transition from current cryptography to quantum-resistant solutions without requiring mass token transfers between wallets.
The Monad proposal is still in its early stages. According to Babel and Kameniš, the published version outlines the general architecture, while a complete technical specification is yet to be developed. If the mechanism is approved, existing accounts will continue to operate unchanged.
It is worth noting that in June, Nicolas Consigny, head of the Kohaku project at the Ethereum Foundation, introduced a concept for post-quantum account protection without the need for a hard fork.