A looming concern in the crypto community is whether quantum computing will destroy Bitcoin’s underlying protocol. People are worried government agencies or other nefarious entities will crack bitcoin’s code with quantum algorithms and undermine blockchain technology. In reality, these fears reflect more of an imagined doomsday scenario than a true statement about future events.
There are two main reasons why bitcoiners should be skeptical about quantum computing threats to blockchain technology. People tend to wallow in fear, uncertainty, and doubt regarding new technology. They assume new technology implies some type of inevitable apocalypse. Many of their omens, however, are steeped in voodoo and superstition. They are either exaggerated or false.
First, Bitcoin’s encryption is not wholly vulnerable to quantum computing. Satoshi Nakomoto knew about the possibility of stronger computer power being able to penetrate encryption, and that is why he built the protocol to withstand attacks. Second, even if a government agency or other organization possessed the talent to bust Bitcoin’s encryption, they would likely forgo the opportunity.
Quantum Computing versus Traditional Computing
Before delving further into these points, it is important to have knowledge of how quantum computers work, and how they differ from traditional machines.
Quantum computers are built on processors containing units called qubits, also called quantum bits. These units take advantage of quantum mechanics by functioning outside the realm of the Newtonian space. In other words, they do not conform to the rules governing the macroscopic, visually perceptible world. They behave according to the mystical order of the subatomic.
Instead of engaging in the binary behavior of 0’s and 1’s in the usual “on” and “off” fashion, quantum computers fuse “0’s” and “1’s,” making them indistinguishable and interconnected.
This paradoxical feature allows quantum computers to make tremendously enormous calculations. For example, to comprehend the difference between a laptop and a quantum computer’s calculation abilities, think of the differences between a horse-drawn chariot and Space-X’s Dragon spacecraft. This analogy expresses how much of an advantage quantum machines have over dinosaur-age computers.
The idea that 0’s and 1’s can be fused is called superposition in quantum physics. This is the idea that on a subatomic scale, particles take on properties of other particles. For instance, it is well known that light can be both a particle and a wave. This phenomenon is called particle-wave duality.
Furthermore, particles can also merge. In accordance with quantum mechanics, they become enjoined in a delicate dance of vibratory ecstasy. This peculiar behavior is called entanglement, and this occurs within the confines of a computer chip the same as it does across the universe-at-large.
When dealing with quantum computers, controlling these states on an microcosmic scale with ultracold processors is difficult. This is the reason why quantum computers have not readily materialized and become commercially available.
Currently, quantum computers are in the early stages of development. They have only been used for specific purposes or specific projects. There is little practical application for them. However, a Newsweek article published on April 7 said they could be implemented sooner rather than later and could be more powerful than our most advanced supercomputer:
“Eventually, quantum computing could outperform the world’s fastest supercomputer—and then all computers ever made, combined. We aren’t there yet, but at 50 qubits, universal quantum computing would reach that inflection point and be able to solve problems existing computers can’t handle, says Jerry Chow, a member of IBM’s experimental quantum computing department. He added that IBM plans to build and distribute a 50-qubit system ‘In the next few years.” Google aims to complete a 49-qubit system by the end of 2017.’
Bitcoin is Naturally Resistant to Quantum Computing
However, regardless of how powerful these computers are and how soon they are created, Bitcoin’s encryption protocol will likely remain safe. There are many questions about what exactly will occur when the black cat is set loose from Pandora’s Box, but some things we know for sure.
Bitcoin’s underlying encryption protocol, SHA-256, is stubbornly resistant to nefarious attempts to undermine it. It is likely strong enough to withstand assaults from even the most savage quantum computer onslaught. A bitcoinnotbombs.com article explained that SHA-256 is formidable enough to handle the attacks:
“In Bitcoin your public key isn’t (initially) made public. While you share your Bitcoin address with others so that they can send you bitcoins, your Bitcoin address is only a hash of your public key, not the public key itself. What does that mean in English? A hash function is a one-way cryptographic function that takes an input and turns it into a cryptographic output. By one-way I mean that you can’t derive the input from the output. It’s kind of like encrypting something then losing the key.”
All of that is a complicated way of saying that while an attacker with a quantum computer could derive the private key from the public key, he couldn’t derive the public key from the Bitcoin address since the public key was run through multiple quantum-resistant one-way hash functions.
Government Incentive to Destroy Bitcoin’s Encryption
Another reason why agencies or other bad actors will not crack the bitcoin code is less obvious. Assuming it was possible to exploit, they might not want to crack it. This sounds silly…because breaking bitcoin’s encryption would help government protect their antiquated financial monopoly from bitcoin’s rapid, decentralized growth. There are good reasons, though.
If they choose to crack the protocol, they expose their quantum capabilities to their rivals. This spurs their enemies to develop counter-technology. Jamie Redman, writing for Bitcoin.com, elaborated by quoting bitcoin security expert Andreas Antonopoulos,
The last thing they are going to use that on is Bitcoin. Cause the moment you use it on Bitcoin you announce to the world we have quantum cryptography that can break elliptic curve — Guess what happens? Your nuclear rivals upgrade their cryptography very easily and try to implement quantum resistant cryptographic algorithms — of which there is a lot of research and a lot of suitable candidates. And you just blew all of your research and advancement in that technology on fighting a shitty little currency that some weirdos use in Prague.
Of course, there are arguments against this position. There could be individuals within these organizations that could act alone to crack the protocol. Arguably, anyone with the knowledge and technology to dismantle bitcoin’s encryption could do so at anytime—and what is scary—is that no one would know precisely who did it.
The fact that no one has conducted this kind of quantum hack, however, is demonstrated by the fact that everyone’s coins are still stored safely in their wallets.
SHA-384 and the Evolution of Bitcoin
Those involved in the cryptocurrency ecosystem should not lose sleep agonizing over the possibility of random people cracking the protocol. Best case scenario quantum computing is not poised to undermine bitcoin’s foundational technology. Worst case scenario, the technology to attack bitcoin is already here, but no one feels incentivized enough to crack it.
Nonetheless, there is a concern from security experts that the bitcoin protocol should upgrade from SHA-256 to SHA-384, which is a sufficiently more advanced form of cryptography. This would be done as a safety measure, just in case. That is why Satoshi Nakomoto ensured the algorithm could easily be upgraded and enhanced. He knew technology would steadily evolve and he wanted his open-source, peer-to-peer system to evolve with it.
Therefore, even if bad actors decided to lay siege to the protocol, the good guys would have time to re-engineer it to withstand attack. They would likewise be able to improve the encryption mechanism to function in lockstep with the quantum computers that enabled the security breech to begin with. In this sense, Bitcoin’s underlying technology boasts tremendous flexibility in the way it can be tweaked for the purposes of self-defense and maturation over the long-term.