Quantum Cryptography: What Is It and How Secure Is It? (2024)

FAQs

Quantum Cryptography: What Is It and How Secure Is It? ›

Quantum cryptography is a system that is completely secure against being compromised without the knowledge of the message sender or the receiver. That is, it is impossible to copy or view data encoded in a quantum state without alerting the sender or receiver.

While still in its early stages, quantum encryption has the potential to be far more secure than previous types of cryptographic algorithms and is even theoretically unhackable. Unlike traditional cryptography, which is built on mathematics, quantum cryptography is built on the laws of physics.

In theory, quantum cryptography is unhackable, because eavesdropping would always be detected, but its practical uses are limited.

The hope is that quantum computers will not break these four algorithms, he says, although there is always that possibility. According to Moody, no one can guarantee that no one will ever develop a smart new attack that could break a post-quantum cryptographic algorithm.

Quantum computers will be able to break common encryption methods at an alarming speed. Encryption tools currently used to protect everything from banking and retail transactions to business data, documents and digital signatures can be rendered ineffective – fast.

Grover's algorithm is a quantum algorithm for unstructured data that provides a quadratic speedup in the computation over classical computing. This can result in AES-128 being feasible to crack, but AES-256 is still considered quantum resistant—at least until 2050, (as referenced throughout ETSI GR QSC 006 V1. 1.1.)

Cryptocurrencies including Bitcoin are not quantum resistant. They also rely on cryptographic algorithms that are vulnerable to quantum computing attacks. To attack SHA-2 functions with 256-bit states, using Grover's algorithm, 2593 qubits (error corrected) would be required, according to Richard Preston's paper.

Quantum Cryptography Disadvantages

We also haven't quite figured out quantum technology yet. Error rates are relatively high, and fiber-based quantum cryptography only works over fairly short distances. You could increase that distance with repeaters, but that would create weak spots.

Threat actors can store encrypted information and decrypt it in the future when a sufficiently powerful quantum computer exists. Therefore, information with a medium or long lifespan (i.e. it will still require protection in 10 or more years) could be at risk of being decrypted by threat actors.

Post-Quantum Cryptography Set to Replace RSA, ECC Post-Quantum Cryptography Set to Replace RSA, ECC. In the next 10 years, public-key encryption needs to be replaced by post-quantum techniques that can stand up to the new challenges.

How long would it take a quantum computer to crack 256 bit encryption? ›

A 256-bit encryption is considered to be highly secure and it would take classical computers millions of years to crack it. However, quantum computers could potentially crack this level of encryption in mere seconds or minutes.

Researchers typically estimate that it will be many years until quantum computers can crack cryptographic keys—the strings of characters used in an encryption algorithm to protect data—faster than ordinary computers.

In other words, when Shor proved quantum computers would have the ability to break large numbers into their prime factors much faster than classic computers, he proved quantum computers could weaken or break many of the encryption methods we use today.

Challenges of quantum computing

The three main challenges we'll look at include quantum decoherence, error correction, and scalability. Each is a major hurdle on the road to quantum computing, and must be overcome if the technology is to reach full potential.

An attacker can intercept and store encrypted data today, and when quantum computers become feasible, the attacker could decrypt the stored data. If quantum computers are realised in fewer than the number of years the data must be confidential for, the security requirement has been broken.

So, the good news is that quantum-safe cryptography already exists. We are so confident in these new standards that we have already built them into our z16 cloud systems, and are working with clients to integrate them into their security infrastructure.

Quantum-resistant cryptocurrencies typically use a variety of cryptographic families that are believed to be secure against quantum computing attacks. These families include: Hash-Based Cryptography: Relies on the security of hash functions and includes algorithms like the Extended Merkle Signature Scheme (XMSS).

Quantum computers can break RSA encryption, which secures our online data. But there are solutions that are resistant to quantum attacks. One of them is Freemindtronic, an Andorran company that notably uses NFC HSM technology to share AES-256 keys using RSA-4096 encryption, which quantum computers cannot decipher.