(Vitalik)

In response to the sudden availability of #quantumcomputers , posing a threat to user funds, the proposal suggests a recovery fork for #Ethereum . This aims to counter the quantum threat through a hard fork and the introduction of quantum-resistant features, ensuring minimal loss of user funds. The key challenges involve the vulnerability of users' private keys due to quantum computing advancements.

The proposal outlines the following key elements for an Ethereum Improvement Proposal (EIP) to address a quantum emergency:

1. Blockchain Reversion: Roll back the blockchain to the first block indicating large-scale theft.

2. Transaction Type Modification: Disable traditional externally owned account (EOA)-based transactions temporarily.

3. Smart Contract Transaction Inclusion: Add a new transaction type to facilitate transactions from smart contract wallets, potentially integrating RIP-7560.

4. Quantum-Resistant Transaction Type or Opcode: Introduce a new transaction type or opcode enabling users to provide a #STARK proof demonstrating knowledge of a private preimage, a hash function ID, and a public address. Successful proof allows the switch to a new validation code, transforming the account into a smart contract wallet.

5. Batch Proof for Gas Efficiency: Allow a batch proof of multiple STARKs for gas efficiency, maintaining the privacy of individual preimages.

By structuring the recovery fork in this way, users can safeguard their funds through the implementation of quantum-resistant cryptography. The proposal emphasizes the potential immediacy of building the necessary infrastructure to prepare the Ethereum ecosystem for a quantum emergency, ensuring a swift and efficient response to emerging threats.