Quantum Computing and its impact on Cryptography and Cybersecurity

Quantum computing is a field of computing that uses the principles of quantum mechanics to process information. Traditional computers use bits to process information, which can exist in either a 0 or 1 state. However, quantum computers use quantum bits or qubits, which can exist in multiple states at the same time. This means that a qubit can represent not only 0 or 1, but also a combination of these two states at the same time. This property of qubits allows quantum computers to perform calculations much faster than classical computers.

Cryptography is the practice of protecting sensitive information by transforming it into an unreadable format, which can then be decoded only by those who have the correct decryption key. Cryptography is a vital component of cybersecurity, ensuring that private data is secure and protected from unauthorized access or interception.

In the digital era, immense amounts of confidential data are exchanged and stored in the Internet. The security of these transactions and the integrity of the data is crucial and mostly depends on a single concept - computational complexity. Confidential information remains secret because any eavesdropper wanting to read it needs to solve an extremely complex mathematical problem.

Acme Inc. is a successful healthcare research company that uses the latest technologies to provide high quality services to their customers. They store all their research and customer data encrypted at rest with AES-128 in a cloud database.

One day they got hacked and the hacker managed to download a large amount of restricted, encrypted data from the cloud database. Acme Inc. later publicly announced the data breach but assured customers and stakeholders that the breach was not significant as the data stolen was encrypted.

Acme Inc. is unaware that upon quantum advantage the hacker may be able to decrypt the stolen encrypted data.

Types of Cryptography

There are three main types of cryptography: symmetric cryptography, asymmetric cryptography, and hashing.

Symmetric Cryptography

Symmetric cryptography or secret-key cryptography, is a technique that uses the same key for both encryption and decryption. The sender and receiver of the message share the secret key that can encrypt or decrypt messages. The most common algorithm used in symmetric cryptography is the Advanced Encryption Standard (AES).

Asymmetric Cryptography

Asymmetric Encryption encrypts and decrypts the data using two separate yet mathematically connected cryptographic keys. These keys are known as a Public Key and a Private Key. Together, they’re called a Public and Private Key Pair. Asymmetric Encryption eliminates the need for a shared secret key and allows secure communication between two parties without prior communication of the secret keys. The most commonly used algorithm in asymmetric cryptography is the Rivest-Shamir-Adleman (RSA) algorithm.

Hashing

Hashing is a technique that takes an input and produces a fixed length output called a hash value. The hash value is unique for an input and is used to ensure message integrity. Hash functions are used to store passwords securely, as the original password cannot be retrieved from the hash value. One of the most commonly used algorithm for hashing is the Secure Hash Algorithm (SHA).

Impact of Quantum computing on Cryptography

With the advent of quantum computing, traditional cryptography techniques may no longer be sufficient to protect against cyber threats. Quantum computing has the potential to break encryption algorithms that are currently used to protect data. Quantum computing leverages the principles of quantum mechanics to perform complex computations that are beyond the capabilities of classical computers. One of the most significant impacts of quantum computing on cryptography is the ability to break traditional public-key (asymmetric) encryption algorithms, such as RSA and Elliptic Curve Cryptography (ECC).

Shor's Algorithm

Shor's algorithm is a quantum algorithm that can factor large numbers exponentially faster than classical computers. This poses a significant threat to asymmetric cryptography, as RSA encryption relies on the difficulty of factoring large numbers. Once Shor's algorithm can factor large numbers, RSA encryption becomes insecure. This means that the private key, which is used for decryption, can be easily obtained, compromising the security of the entire system.

Grover's Search Algorithm

Grover's search algorithm is a quantum algorithm that can search an unsorted database of n elements in O(√n) time. This poses a significant threat to symmetric cryptography, as symmetric key lengths are chosen to make brute-force attacks infeasible. Grover's algorithm makes brute-force attacks more feasible by reducing the effective key length by a factor of √n.

Mitigations

To mitigate the threat of quantum computing, researchers have been exploring various options including post-quantum cryptography and Quantum Key Distribution (QKD).

Post-quantum cryptography

Post-quantum cryptography refers to cryptographic systems that are resistant to attacks from both classical and quantum computers. Post-quantum cryptography involves developing encryption algorithms that are resistant to quantum attacks. These algorithms are designed to work effectively against attacks that use Quantum techniques, ensuring that sensitive data remains secure. Post-quantum cryptography includes algorithms such as lattice-based cryptography, code-based cryptography, and hash-based cryptography.

Quantum cryptography And Quantum Key Distribution (QKD)

Quantum cryptography is another approach to ensure secure communications in the age of quantum computing. Quantum cryptography relies on the principles of quantum mechanics to create unbreakable encryption schemes.

Quantum key distribution (QKD), uses quantum mechanics to generate a shared secret key between two parties that can be used for secure communication. QKD relies on the Heisenberg uncertainty principle, which states that it is impossible to measure certain properties of a quantum particle without disturbing it, ensuring that any attempt to intercept the key will be detected. QKD enables two parties to generate a shared secret key, which can then be used for symmetric encryption thereby ensuring secure communication.

The rise of quantum computing has the potential to threaten the security of traditional cryptography. However, new techniques are being researched and developed that offer promising solutions to ensure that sensitive data remains secure. As the development of quantum computing progresses, it is essential that we continue to implement secure cryptography techniques to protect against such cyber threats.

References

https://www.cisco.com/c/dam/global/en_uk/products/security/seccon/sam-samuel.pdf