Coinbase Warns Quantum Computing Could Break Blockchain Cryptography

Coinbase's quantum researchers have highlighted Algorand and Aptos' work to prepare their networks for potential threats from quantum computing in a report on Tuesday, as they warned that other proof-of-stake chains may be more vulnerable to attacks.

Coinbase's Independent Advisory Board on Quantum Computing and Blockchain released a paper outlining the threat that quantum computers pose to blockchains and suggested ways to prepare networks for the technology. "A sufficiently powerful quantum computer could one day break the cryptography that secures digital assets across major blockchains," Coinbase said. "The board has high confidence this type of machine will eventually be built."

Quantum computers are an emerging technology expected to be significantly more powerful than today's top supercomputers, which has some crypto analysts worried that the technology could eventually crack blockchains' algorithms and break into crypto wallets.

Algorand and Aptos more prepared for quantum

Coinbase said in its report that the layer-1 blockchain Algorand has a "staged roadmap toward full quantum readiness," and is among the first networks to have deployed cryptography designed to be secure against quantum computers. "At the transaction and execution layers, Algorand already provides the cryptographic tools necessary to support quantum-resistant accounts," the report said, adding that users can create such accounts "without requiring protocol modifications."

It added that Algorand had recently completed its first quantum-resistant transaction on mainnet, but block proposals and committee voting mechanisms "remain vulnerable to quantum attacks," which the blockchain is researching ways to secure.

Coinbase said that Aptos, a competing layer-1 blockchain, was "well positioned for the transition to post-quantum secure transactions." It explained that on Aptos, a user's public key is stored as metadata associated with the account, and a user's address isn't derived from the hash of the user's public key. "Users who want to become post-quantum secure need only sign a transaction that updates their authentication key to a post-quantum public key," Coinbase said. "There is no need to move assets to a new account."

Proof-of-stake chains may be at greater risk

Coinbase warned that proof-of-stake blockchains, including Ethereum and Solana, may be at greater risk to quantum computing because of the signature schemes validators use to secure the network, according to the board.

However, Coinbase acknowledged that Solana has created a new signature scheme, and users can move their tokens to a new address based on the upgraded scheme and will be "no longer exposed to a quantum attacker." Ethereum, too, "has a clear roadmap to address this in the near future," Coinbase said, which includes upgrading signatures to be quantum-resistant.

The report also discussed how networks could deal with quantum-vulnerable tokens and wallets, suggesting that blockchains could tell their users to migrate to quantum-proof wallets and that wallets with assets that are quantum-vulnerable would be revoked and lost forever. However, the board said that the threat of quantum computing "doesn't exist yet," as a computer that could threaten crypto "would need to be orders of magnitude more powerful than anything available today," which could take at least a decade.