Is quantum computing a threat to Bitcoin? How can Bitcoin become more secure against a quantum computing attack? Will this upgrade require moving coins to new addresses? Will it be implemented as a soft or hard fork? What happens to coins controlled by lost keys? These are the questions Andreas Antonopoulos, a technologist and serial entrepreneur, is addressing in this video.
A Different Kind of Computing
While much of the world is captivated by the meteoric rise of bitcoin’s value, others are focused on the technology behind the cryptocurrency: blockchain. The decentralized digital ledger tech is built upon a peer-to-peer network, and it is far more secure than the centralized systems used by traditional banks and financial institutions. However, another revolutionary technology is now threatening Bitcoin’s security.
In a recently published paper, Divesh Aggarwal and his colleagues from the National University of Singapore (NUS) examined how quantum computers could undermine and even exploit Bitcoin’s security protocols.
As explained by the MIT Technology Review, these protocols use algorithms to turn data into mathematical functions. Every transaction is recorded into “blocks” using these functions as part of the computationally demanding work of cryptocurrency mining.
These cryptographic protocols make cracking a blockchain using today’s computers practically impossible, but the system does have weak points quantum computers could exploit.
Cryptography Gets Busted
For their paper, Aggarwal and his colleagues examined how quantum computers could break through Bitcoin’s security in two ways: by mining more than classical computers can and by cracking Bitcoin’s cryptographic keys.
If a miner controls more than 50 percent of the computational power on a blockchain network, they can use that majority control for malicious activity. The researchers found that the application-specific integrated circuits (ASICs)currently used by most cryptocurrency miners should be able to maintain a speed advantage over quantum computers for the next 10 years, so miners likely won’t be able to use quantum systems for nefarious purposes in this manner for at least a decade.
As for cracking today’s cryptographic keys, part of Bitcoin’s security protocol involves every bitcoin owner possessing two encryption keys: a private one and a public one. The latter can be easily generated using the former, but the reverse is far more difficult. An owner’s signature is verified without revealing the private key using a technique called elliptic curve signature scheme.
While conventional computers don’t possess the necessary computational power to derive a private key from a public key, quantum computers could do it rather easily. “The elliptic curve signature scheme used by Bitcoin…could be completely broken by a quantum computer as early as 2027,” Aggarwal and his colleagues wrote.