Moving towards quantum resistant encryption algorithms (2024)

FAQs

What encryption algorithms are quantum resistant? ›

Secure communication methods using IKEv1 combined with pre-shared keys and using the AES-256 (symmetric) encryption algorithm are the best bet for quantum-safe applications.

It turns out that all current asymmetric cryptography implementations, including RSA, Diffie-Hellman, and elliptic curve cryptography, are theoretically breakable by quantum computers. Interestingly, the less mathematical encryption approach, symmetric cryptography, is less susceptible.

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.

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.)

Even encrypted data that is safe against current adversaries can be stored for later decryption once a practical quantum computer becomes available. At the same time it will be no longer possible to guarantee the integrity and authenticity of transmitted information, as tampered data will go undetected.

The abrupt shutdown of NASA's quantum computing project was triggered by an unforeseen incident during a routine test. During the analysis of a complex simulation, the quantum computer demonstrated unprecedented computational power, solving a previously intractable problem.

Even if you had a quantum computer with millions of qubits (which we don't have yet), it would still take years or decades to crack 256 bit encryption.

Capture and decrypt attacks

In this situation, the data is already at risk. An attacker can intercept and store encrypted data today, and when quantum computers become feasible, the attacker could decrypt the stored data.

That same traditional computer would take 34,000 years to crack a password that was 12 characters and consisted of at least one upper case character, one number, and one symbol. To sum that up: password – cracked instantly. PassWorD – cracked in 22 minutes.

The size of a quantum computer is measured in quantum bits, or qubits. Researchers say it might take one million or more qubits to crack RSA.

Why is quantum encryption unbreakable? ›

For example, it is impossible to copy data encoded in a quantum state. If one attempts to read the encoded data, the quantum state will be changed due to wave function collapse (no-cloning theorem).

Quantum computers also threaten the security of hash functions like SHA-256 by utilizing Grover's algorithm. Grover's algorithm can search unsorted databases quadratically faster than classical algorithms, making brute-force attacks on hash functions more feasible.

Grover's algorithm can reduce the brute force attack time to its square root. So for AES-128 the attack time becomes reduced to 2⁶⁴ (not very secure), while AES-256 becomes reduced to 2¹²⁸ which is still considered very secure.

According to the Kryptera researchers, breaking AES-128 encryption should require a quantum computer with 2,953 logical qubits, while breaking AES-256 would need 6,681 qubits. Then there is the “Shor” algorithm, which can break asymmetric encryption with twice as many qubits as the key size.

While a 256-bit hash is still considered secure against classical attacks, it is theoretically as secure as a 128-bit hash against quantum attacks.

Because 128 bit security is still adequate, a quantum computer cannot break 256 bit AES. However a quantum computer could still cause big problems for the public key algorithms (like elliptic curves) that are necessary to exchange symmetric keys for AES based secure channels.

The quantum data sender can still go for hom*omorphic encryption of the data. In this case, the second quantum device does not know what it is processing and maintains the security of the data, which is otherwise impossible. Still, the transfer of quantum states, encrypted or otherwise, is a major challenge.

NIST announced its selection of four algorithms — CRYSTALS-Kyber, CRYSTALS-Dilithium, Sphincs+ and FALCON — slated for standardization in 2022 and released draft versions of three of these standards in 2023. The fourth draft standard based on FALCON is planned for late 2024.