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How To Protect Your Data in Quantum Age

A quantum computer represents a groundbreaking paradigm shift in computing, leveraging the intricate principles of quantum mechanics to execute certain computations exponentially faster than their classical counterparts.

Release Date: 7 Mar 2024 3942 Views

While classical computers rely on binary units known as classical bits, denoted as 0 or 1, quantum computers operate on an entirely different mechanism. They use quantum bits, or qubits, which possess the unique ability to exist in a superposition of states, simultaneously representing both 0 and 1. This property empowers quantum computers to explore multiple states concurrently. Moreover, qubits can become entangled, signifying that the state of one qubit can be intricately linked to another, even when separated by vast distances.


Quantum algorithms harness these characteristics to perform complex calculations with superior efficiency compared to classical computers for specific tasks, such as quantum world simulation, algorithm speedup, and artificial intelligence.


Apart from running quantum algorithms, quantum computers also can execute classical algorithms. However, due to the running environment and error correction of quantum computers, it is more efficient and cost-effective to execute day-to-day processing tasks such as word processing and spreadsheet calculation on classical computers. Therefore, it is believed that quantum computers would not replace classical computers, they would operate on different tasks instead.



Quantum Algorithm: A Potential Threats to Data Encryption

In contemporary digital communication, encryption stands as the vanguard of data security, ensuring the confidentiality and privacy of sensitive information. There are two major methods in modern encryption: symmetric and asymmetric encryption. The former, known as "symmetric," refers to a method where the sender and receiver share a single secret key generated from pseudorandom number. The key can be used for both encryption and decryption. Due to its efficiency, symmetric encryption is widely used in data transmission and storage encryption.


Asymmetric encryption, on the other hand, requires the use of different keys for encryption and decryption. A public key is used for encryption, while its corresponding private key is used for decryption. When generating the keys, two random prime numbers are multiplied together to generate a very large integer, which becomes part of both the public and private keys. For hackers, cracking the key requires finding the prime factors of that integer, a process known as prime factorisation (for example, the integer 3233 can be factored into the primes 61 and 53). However, this process takes the hacker a lot of time. Even though prime factorisation may be relatively easy for small numbers, there is no known fast algorithm that can solve this problem efficiently for large numbers. For example, given a 1000 digits number which is the product of two very large prime numbers, it may take billions of attempts to find the combination of these two large prime numbers. It requires a lot of computational time and resources, and makes cracking the encrypted message very difficult.


Therefore, prime factorisation plays a critical role in asymmetric encryption algorithms, ensuring its security by making it infeasible for hackers to crack encrypted messages.



Breaking Cryptography

Against the backdrop of the rise of quantum computing, Grover's algorithm proposed by Lov Kumar Grover poses a certain degree of threat to symmetric encryption, but it can only shorten the time to crack symmetric keys to some extent, which has a relatively small impact.


In contrast, Shor's algorithm proposed by Peter Shor could revolutionise today's asymmetric encryption. The algorithm leverages the superposition and quantum entanglement properties of quanta to drastically reduce the computation time for prime factorisation. For example, if we use the RSA encryption with 2048 bits RSA key, it may take a conventional computer 30 billion years to crack it. But if we use a quantum computer and apply the Shor’s algorithm, theoretically a hacker can crack the key within just 8 hours using a quantum computer of 20 million qubits. This breakthrough demonstrates the vulnerability of modern cryptography to the challenge of quantum computers.


Although current quantum technology has not yet been able to implement the Shor’s algorithm to break asymmetric encryption, with the advancement of technology and the invention of the new factorisation method, it is not impossible to break any existing encryption method swiftly, and people have even named the future day that quantum computers can be truly applied to break asymmetric encryption as Q-Day.


In addition, many people are concerned that hackers may collect existing encrypted data and decrypt it once quantum computers become powerful enough, which could pose a serious threat to data security.  



Current Quantum Computers Pose a Relatively Low Threat to Data Encryption

At present, quantum computer development is less likely to pose an immediate threat to current data encryption application for several compelling reasons.


  • Firstly, large-scale quantum computers capable of breaking widely-used encryption algorithms remain in the theoretical and experimental phase and are not yet readily accessible.
  • Secondly, until now, there is no empirical evidence on running Shor’s algorithm to break the modern suggested encryption standard RSA-2048 (i.e. factoring a 617-digits natural number) because it requires capabilities beyond the current technology.
  • Thirdly, the security level of both techniques depends on the length of the key, i.e. the longer the key is, the longer it takes to crack it, If the key size of symmetric encryption is large enough, there is no quantum algorithm to break it in a short time.
  • Fourthly the establishment and maintenance of stable, error-corrected quantum computers pose formidable technological challenges.
  • Furthermore, even if such quantum computers were to be realized, they would necessitate substantial resources and infrastructure.



Post-quantum cryptographic algorithms and their challenges

Although current quantum computing development cannot directly threaten modern encryption, concerns persist regarding the vulnerability of existing encrypted data when practical quantum computers become available. To address this concern, computer scientists and cryptographers are actively working on post-quantum cryptographic algorithms designed to protect data from quantum computers. These post-quantum cryptographic algorithms involve complex mathematical problems, approaches including Lattice-based cryptography and Hash-based Cryptography, etc., which are believed to be computational hard for both quantum and classical computer.


National Institute of Standards and Technology (NIST) of the United States selected 4 algorithms and is standardising them. Those 4 algorithms are CRYSTALS-Kyber (used in data encryption), CRYTRALS-Dilithium, SPHINCS+ and FALCON (used in digital signature). Two noteworthy applications include instant messaging application Signal’s 'PQXDH Protocol' (based on CRYTRALS-Kyber) and the 'FIDO2 security key' (based on CRYTRALS-Dilithium) introduced by Google. NIST would continue to evaluate different post-quantum cryptographic algorithms and may publish more in the future.


However, it's essential to note that even these post-quantum cryptography methods may face challenges, as demonstrated by the recent vulnerability discovered on CRYSTALS-Kyber public-key encryption. The research team used recursive training AI to break it by running deep learning analysis on measurable information such as timing and power consumption of devices using this encryption method. This highlights the need for ongoing research and adaptability in safeguarding our data against quantum threats.


Given that many post-quantum cryptographic algorithms are still in the early stages of development, one approach is hybrid cryptography to protect the data. This approach uses both classical encryption and post-quantum cryptography methods to encrypt data, ensuring data protection without relying solely on post-quantum cryptography.




Quantum computing is a fascinating technology which represent the new page of computing. While quantum computers excel in specific tasks, they also pose challenges to traditional data encryption techniques. Despite the current technological limitations, the proactive development of post-quantum cryptography methods opens up new possibilities for data security in a quantum-enabled future. However, these methods are not without challenges, and ongoing research and adaptability will be essential to stay ahead of evolving quantum threats. As we navigate this complex landscape, hybrid cryptography provides a promising approach to secure our data effectively, leveraging both classical and post-quantum cryptography techniques.


In the future digital era, with the development of quantum technology, it will become more crucial to protect the data security of individuals and organizations. In order to cope with quantum threats, HKCERT recommends everyone to pay attention to the development of post-quantum encryption methods and adopt hybrid encryption technology to ensure data security. It is also essential to pay more attention to data security, such as data classification, access control, key management, segregation of data storage and backup, data loss prevention, etc.. Only through continuous vigilance we can enhance the data security of individuals and organizations, and build a secure network environment for the future.