Blockstream Says Bitcoin Can Counter Future Quantum Threats With New Signature Technology

Blockstream, a Bitcoin infrastructure company, has released research showing Bitcoin could prepare for future attacks from quantum computers by adopting a new digital signature technology.

In its third-quarter business update published on Nov. 5, Blockstream highlighted research aimed at countering the threat posed by quantum computers. The team had previously published an August report comparing three lattice-based signature schemes: Dilithium, Falcon and Hawk.

Digital signatures verify that the sender of Bitcoin has the right to spend the asset. The signature method currently in use could be vulnerable if sufficiently powerful quantum computers emerge. The researchers said Bitcoin needs to prepare for a transition to a new signature system regardless of when such machines arrive.

Among the options reviewed, Falcon-1024 was assessed as offering the best balance of data size, verification speed and the maturity of the research underlying its security foundations. “If we had to choose a lattice-based signature scheme for Bitcoin today, we would pick Falcon-1024,” the team wrote.

The researchers identified several key challenges, including finalizing the Falcon standard, securing validated implementations and addressing the memory burden on hardware wallets. They also said there is still no practical solution for deriving and managing multiple public keys from a single master public key, as existing wallets do today.

The team said hash-based signatures are the more conservative choice in the near term because their security foundations have been tested for longer. Once Falcon standardization and implementation technology mature, it added, combining the two approaches could also be considered to improve security and processing efficiency.