Introduction
There have been some repercussions in the Bitcoin investment community since Google CEO Sundar Pichai recently revealed their new quantum computer device, "Willow." For Bitcoin naysayers, it was like bait in the sea. Geiger Capital joked that "Bitcoin is dead" in a widely shared tweet, but many detractors seized the opportunity to trash the cryptocurrency. Every few years, concerns about bitcoin and quantum computing (QC) make headlines, maybe sparked by Google's consecutive chip releases. Are the worries, however, warranted? Is there a real chance that quantum computers may "crack" Bitcoin?
I'll go over the fundamentals of quantum computing, the operation of Bitcoin's cryptographic architecture, and why QC is not at all a danger in this essay. In order to put these concerns into perspective, we will also examine how Bitcoin's cryptography can change if necessary.
101 of Quantum Computing
Fundamentally, quantum computing is a groundbreaking method for resolving mathematical issues. Quantum computers employ qubits, which can exist in a state of 0, 1, or both simultaneously—a phenomenon known as superposition—in contrast to classical computers, which use bits (0s and 1s). Because of this, some calculations can be completed by quantum computers ten times faster than by conventional computers.
Entanglement, in which one qubit's state is closely connected to another, is another feature used by quantum computers. They tackle mathematical problems that would otherwise take billions of years for classical computers to solve using previously developed quantum algorithms like Shor's and Grover's.
However, there is a catch: existing machines are not large enough to handle real-world cryptographic systems like Bitcoin or public key cryptography, are prone to errors, and require extreme circumstances like temperatures close to absolute zero.
The Quantum Threat And The Cryptography Of Bitcoin
A cryptographic technique called SHA-256 is used by Bitcoin to safeguard its blockchain, proof-of-work mining, and contemporary wallets. Bitcoin is extremely resistant to traditional computational assaults,
- Such as rewriting history or cracking private keys and stealing money, because to this encryption. For example, it would take 2256 operations to brute-force a Bitcoin private key, which is so much that it is almost impossible.
- Grover's Algorithm might conceivably be used by quantum computers to reduce the number of operations needed to 2128, which would theoretically make the problem easier to solve. But this still requires a level of computing power that is far beyond human capabilities.
- For instance, depending on the required speed, the University of Sussex calculates that 13 million to 317 million qubits would be needed to crack SHA-256 in a realistic amount of time. In contrast, the Willow processor from Google only has 105 qubits
- Furthermore, from the start, Bitcoin creators were aware of the possible quantum hazard. The concern was addressed by Satoshi Nakamoto, the founder of Bitcoin, in 2010, and the Bitcoin Wiki's quantum commuting article was written in 2016. The best practices for Bitcoin were also developed with this type of attack in mind.
Addresses are typically used in wallets just once, reducing vulnerability to these attacks. A quantum attacker has a brief window of opportunity to compromise the key before funds are transferred to a new key in the new block since public keys and the associated signature are only made public when a transaction is sent but not confirmed.
Reality versus Quantum Hype
Google's claims of quantum supremacy have been criticized by physicist Sabine Hossenfelder as being overblown. She pointed out that previous claims made in 2019 regarding a 50-qubit processor were promptly contested by IBM
- And subsequently duplicated on traditional computers in a similar amount of time. Although Willow's statement is amazing from a scientific standpoint, she claims that "the consequences for everyday life are zero."
- Gil Kalai, a mathematician and computer scientist, agreed. "Google Quantum AI's claims (including published ones) should be approached with caution, particularly those of an extraordinary nature," he wrote in a blog post on the day of the Willow announcement, urging prudence.
- These assertions might be the result of serious methodological mistakes, which means they might more accurately represent the expectations of the researchers than the actual state of science.
- Quantum computing is still in its infancy by most standards. Technologies such as Google's Willow chip are far from being able to break the SHA-256 algorithm or interfere with the Bitcoin network. Other cryptographic systems, including RSA and ECC.
Which are frequently used in secure messaging, financial services, and military applications, would probably be compromised well before that time since they are more susceptible to quantum assaults than hashing algorithms like SHA-256. This suggests that Bitcoin may be safer than a lot of the conventional methods in use today.
Bitcoin is Adaptable If Needed
Although they represent an interesting technological frontier, quantum computers are still distant from being a serious danger to the cryptography of Bitcoin.
Bitcoin might become vulnerable as QC develops, but only after attacks on other cryptographic systems—such as banks and military applications—that have weaker encryption have been launched.
Although QC development is questionable, this concern is still decades away based on advancements over the last five years. Meanwhile, Bitcoin already has solutions in place.
Its decentralized structure enables the kind of protocol changes required to fix these problems. For years, there has been discussion on quantum-resistant algorithms such as Lamport signatures and new address types through soft forks.
More than any flaws in Bitcoin, the recent eulogies for the cryptocurrency accompanying the Willow chip revelation are the result of confirmation bias on the part of critics. Bitcoin is still alive. Not at all.
Bitcoin is more resilient and forward-thinking than other technologies that might be at risk from the threat posed by quantum computing because of its strong current cryptography and a clear route to quantum resistance if necessary.
