Why quantum computing isn’t a threat to crypto… yet

Quantum computing has raised concerns about the future of cryptocurrency and blockchain technology in recent years. For example, it is commonly assumed that highly sophisticated quantum computers will one day be able to crack today’s encryption, making security a serious concern for users in the blockchain space.

The SHA-256 encryption protocol used for Bitcoin network security is currently unbreakable by today’s computers. However, experts expect that within a decade, quantum computing will be able to break existing encryption protocols.

As for whether holders should be concerned about quantum computers being a threat to cryptocurrency, Johann Polecsak, CTO of QAN Platform, a layer-1 blockchain platform, told Cointelegraph:

“Absolutely. Elliptic curve signatures – which power all major blockchains today and are proven to be vulnerable to QC attacks – will break, which is the ONLY authentication mechanism in the system. Once it breaks, it will be literally impossible to distinguish between a legitimate wallet owner and a hacker who has forged a signature of one.”

If the current cryptographic hashing algorithms are ever cracked, it will leave hundreds of billions worth of digital assets vulnerable to theft by malicious actors. Despite these concerns, quantum computing still has a long way to go before it becomes a viable threat to blockchain technology.

What is quantum computing?

Modern computers process information and perform calculations using “bits”. Unfortunately, these pieces cannot exist simultaneously in two places and two different states.

Instead, traditional bits of data can either have the value 0 or 1. A good analogy is that a light switch is turned on or off. Therefore, if there is a pair of bits, for example, those bits can only contain one of the four potential combinations at any time: 0-0, 0-1, 1-0, or 1-1.

From a more pragmatic point of view, the implication of this is that it would probably take an average computer quite a long time to complete complicated calculations, namely those that have to take into account every single potential configuration.

Quantum computers do not operate under the same constraints as traditional computers. Instead, they use something called quantum bits or “qubits” instead of traditional bits. These qubits can coexist in states 0 and 1 at the same time.

As mentioned earlier, two bits can only contain one of four possible combinations at the same time. However, a single pair of qubits is capable of storing all four simultaneously. And the number of possible options grows exponentially with each additional qubit.

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As a consequence, quantum computers can perform many calculations while simultaneously considering several different configurations. Consider, for example, the 54-qubit Sycamore processor that Google developed. It was able to complete a calculation in 200 seconds that would have taken the most powerful supercomputer in the world 10,000 years to complete.

Simply put, quantum computers are much faster than traditional computers since they use qubits to perform multiple calculations simultaneously. Additionally, since qubits can have a value of 0, 1, or both, they are much more efficient than the binary bit system used by current computers.

Different types of quantum data attacks

So-called storage attacks involve a malicious party attempting to steal cash by targeting susceptible blockchain addresses, such as those where the wallet’s public key is visible in a public ledger.

Four million Bitcoin (BTC), or 25% of all BTC, are vulnerable to a quantum computer attack due to owners using unhashed public keys or reusing BTC addresses. The quantum computer must be powerful enough to decipher the private key from the unhashed public address. If the private key is successfully decrypted, the malicious actor can steal a user’s funds directly from the wallet.

However, experts expect that the computing power required to carry out these attacks will be millions of times more than today’s quantum computers, which have less than 100 qubits. Nevertheless, quantum computing researchers have assumed that the number of qubits in use could reach 10 million within the next ten years.

To protect against these attacks, crypto users must avoid reusing addresses or moving their funds to addresses where the public key has not been published. This sounds good in theory, but it may prove too tedious for everyday users.

Someone with access to a powerful quantum computer can attempt to steal money from a blockchain transaction in transit by launching a transit attack. Because it applies to all transactions, the scope of this attack is far broader. However, it is more challenging to execute it because the attacker has to complete it before the miners can execute the transaction.

In most circumstances, an attacker does not have more than a few minutes due to the confirmation time on networks like Bitcoin and Ethereum. Hackers also need billions of qubits to carry out such an attack, making the risk of a transit attack much lower than a storage attack. Nevertheless, it is still something users should keep in mind.

Protecting against abuse during transport is not an easy task. To do this, it is necessary to change the underlying cryptographic signature algorithm of the blockchain to one that is resistant to a quantum attack.

Measures to protect against quantum computing

There is still a significant amount of work to be done on quantum computing before it can be considered a credible threat to blockchain technology.

In addition, blockchain technology will most likely evolve to address the issue of quantum security once quantum computers are widely available. There are already cryptocurrencies such as IOTA that use DAG (directed acyclic graph) technology which is considered quantum resistant. Unlike the blocks that make up a blockchain, directed acyclic graphs are made up of nodes and connections between them. Thus, records of crypto transactions take the form of nodes. The records of these exchanges are then stacked on top of each other.

Block lattice is another DAG-based technology that is quantum resistant. Blockchain networks like the QAN Platform use the technology to enable developers to build quantum-resistant smart contracts, decentralized applications and digital assets. Lattice cryptography is resistant to quantum computers because it is based on a problem that a quantum computer may not be able to solve easily. The name given to this problem is the Shortest Vector Problem (SVP). Mathematically, SVP is a matter of finding the shortest vector in a high-dimensional lattice.

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It is believed that the SVP is difficult for quantum computers to solve due to the nature of quantum computing. Only when the states of the qubits are perfectly aligned can the superposition principle be used by a quantum computer. The quantum computer can use the superposition principle when the states of the qubits are perfectly aligned. Nevertheless, it must resort to more conventional calculation methods when the states are not. As a result, it is highly unlikely that a quantum computer will succeed in solving the SVP. This is why lattice-based encryption is secure against quantum computers.

Even traditional organizations have taken steps toward quantum security. JPMorgan and Toshiba have teamed up to develop quantum key distribution (QKD), a solution they claim is quantum resistant. Using quantum physics and cryptography, QKD enables two parties to trade confidential data while identifying and thwarting any efforts by a third party to eavesdrop on the transaction. The concept is seen as a potentially useful security mechanism against hypothetical blockchain attacks that quantum computers might carry out in the future.