Quantum cryptography is a rapidly expanding field in quantum information science with the frequent design of new protocols, constant security improvement, and a transition from lab demonstrations to real-world implementation. The industry is growing fast to commercialize the technology.
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What is Quantum Cryptography?
Conventional public key cryptography uses mathematical functions like factorization to encode information in a way that would take current computers many years to break. However, working quantum computers (which are not yet a reality) could theoretically break this kind of encryption in a matter of days, hours, or seconds.
Quantum cryptography has been developed to secure electronic communications by applying the peculiar laws of quantum mechanics to computer algorithms. This technology produces a random bit string that is only known to two parties, who can use it to encrypt and decrypt electronic communications.
One useful property of quantum cryptography is the ability to tell if anybody is “eavesdropping” on secure communication. This is possible because of the effect observation has on quantum states: measuring a quantum system alters it. If a third party tries to read the information that was transmitted in a quantum state, that information will be altered and the eavesdropping can be detected.
Governments Play a Major Role in Quantum Cryptography Development
Cryptography provides security for daily activities like sending emails, online purchases, and ATM transactions by keeping data private and authenticating identity. The strength of modern cryptography is based on the difficulty of solving mathematical problems with classical computers or finding secret keys/messages. However, quantum computers work differently and can solve these problems in hours/minutes, making current encryption methods vulnerable. To address this, "quantum-safe cryptography" aims to identify algorithms that can withstand both classical and quantum computer attacks. Quantum computers use qubits instead of bits, enabling them to perform multidimensional quantum algorithms and solve complex problems.
Current public key cryptography, which revolutionized secure communication in the 1970s, is vulnerable to quantum attacks. Therefore, new math is needed to keep information secure. Experts predict that large-scale quantum computers capable of breaking current algorithms could be available by the end of the decade. Encrypted data stored today could also be decrypted later using quantum computers, so it is important to move to quantum-safe solutions.
Governments in the US, Germany and the UK are already taking action to implement quantum-safe cryptography. There is unlikely to be a single algorithm suitable for all applications due to varying performance characteristics and the expanding requirements for cryptography. Research into quantum-safe cryptography is ongoing, but security against classical and quantum attacks is still better understood for some algorithms over others.
Quantum Cryptography is a Growing Sector
The quantum cryptography market was estimated to be $89 million in 2020. Analysts predict it will keep growing at a CAGR of 19.1% to reach $214 million in 2025.
Increased digitization increases the need for secure transmission of information, and the COVID-19 pandemic sped up the pre-existing trend of digitization across all industry sectors. For example, in healthcare, most physicians are now keeping digital records. In many countries including the United States, these records must be kept secure by law.
While there is no working quantum computer that can break traditional cryptography as yet, scientists and industry commentators expect such technology to mature by the end of this decade. This means that information sent now could be intercepted and stored by a malicious party and then decrypted in the future when the technology is there to do it.
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Because of this, there are a number of companies offering advanced quantum cryptography services in the market already.
CryptoNext Security, a French startup, is providing cryptographic standards to secure IT infrastructure. IdQuantique is a Swiss company that upgrades existing enterprise-level encryption with quantum cryptography. Qrypt, a New York-based technology startup, is another major player in this sector. Single Quantum is a Dutch provider with technology that can detect single photons with high precision for photonic (and quantum) communications.
Back to the Classics: Post-Quantum Encryption
Quantum cryptography may be impractical on a major scale, as it relies on hardware that is currently very complex and costly to produce and operate. Because of this, researchers have introduced a new field known as post-quantum encryption.
Much of this new encryption avoids the use of factoring entirely, relying on different mathematical functions that are less easy for quantum computers to resolve.
Government agencies like NIST (the National Institute of Standards and Technology) in the United States anticipate a quantum computing future and are inviting the wider research community to develop new strategies and algorithms for post-quantum cryptography.
Technologies under development include lattice-based cryptography and hash-based cryptography.
Lattice-based cryptography works by representing mathematical problems as high-dimensional lattices. The security of these cryptographic systems lies in the difficulty of solving mathematical problems in these lattice structures. The process involves transforming data into a lattice and applying various operations to encrypt the data. The secret key consists of the parameters used in these operations, which makes it very difficult for an attacker to deduce the original data from the encrypted form. This makes lattice-based cryptography an attractive alternative to post-quantum cryptography.
Hash-based cryptography uses hash functions to provide data integrity and authenticity. The hash function takes an input message and computes a fixed-size output (hash value), which is unique to the input. The hash value can be used to verify if the message has been changed, as even a small change in the input message results in a completely different hash value. The hash value is then encrypted with the sender's private key to produce a digital signature, which is transmitted along with the message. The receiver then uses the sender's public key to decrypt the digital signature and computes the hash value of the received message. If the hash values match, the message is considered authentic and unmodified.
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References and Further Reading
Cryptography in the Quantum Age. (2022) [Online] NIST. Available at: https://www.nist.gov/physics/introduction-new-quantum-revolution/cryptography-quantum-age (Accessed on 30 January 2030).
Dames, A., and E. Richuso (2022). What Is Quantum-Safe Cryptography, and Why Do We Need It? [Online] IBM. Available at: https://www.ibm.com/cloud/blog/what-is-quantum-safe-cryptography-and-why-do-we-need-it (Accessed on 30 January 2023).
Dilmegani, C. (2022). Quantum Cryptography/Encryption in 2023: In-Depth Guide. [Online] AI Multiple. Available at: https://research.aimultiple.com/quantum-cryptography/ (Accessed on 30 January 2023).
Forecast 2028 for the Quantum Cryptography Market in terms of size, returns, gross margin, and market share. (2023) [Online] Marketwatch. Available at: https://www.marketwatch.com/ (Accessed on 30 January 2023).
Pirandola, S., et al (2020). Advances in quantum cryptography. Advances in Optics and Photonics. doi.org/10.1364/AOP.361502.
Preparing for Quantum-Safe Cryptography. (2020) [Online] NCSC. Available at: https://www.ncsc.gov.uk/whitepaper/preparing-for-quantum-safe-cryptography (Accessed on 30 January 2023).
Quantum cryptography. [Online] Phys.org. Available at: https://phys.org/tags/quantum+cryptography/ (Accessed on 30 January 2023).
Quantum Cryptography Market. (2020) [Online] Markets and Markets. Available at: https://www.marketsandmarkets.com/Market-Reports/quantum-cryptography-market-45857130.html (Accessed on 30 January 2023).