Cybersecurity: Anssi seriously anticipates the quantum threat and will adapt its visas

Quantum computers should in theory be able to break existing cryptographic algorithms, which will undermine data security in the long run. This is a threat that must be taken seriously, according to the National Information Systems Security Agency (Anssi), which published a position on January 4, 2022 on the transition to post-quantum cryptography.

Advise industrialists
This document fulfills two objectives: to provide guidance to manufacturers developing security products, and to present a provisional agenda for the transition in terms of security visas. All to prepare for the era of quantum computing by developing algorithms that are robust enough to fight against attacks carried out by quantum computers.

The security of the majority of digital infrastructures is based on public key cryptographyalso called cryptography asymmetric, details the French cybersecurity policeman. It uses a key accessible only to the recipients of the messages, allowing them to be decrypted. This technique is mainly used for authentication Where electronic signature.

Asymmetric cryptography relies on “two mathematical problems sized to be virtually impossible to solve with our current computing resources and knowledge“, explains Anssi. However, a quantum computer could in theory allow hackers to exploit quantum properties to find the secret key faster.

Indeed, quantum computing opens up the possibility of realizing much more efficient algorithms than those executable on a conventional computer. Schematically, instead of using bits (of a binary value of 0 or 1), quantum computers are built around “quantum bits” or qubits. Each qubit consists of a superposition of two basic states which correspond to probability amplitudes. By increasing the number of qubits, power increases exponentially.

Find new means of defense
These computers have been considered theoretically for several decades. So far, no quantum computer large enough to run these algorithms on cryptographic parameters has been built. According to Anssi, such computers could be completed in the coming decades. But this threat must all the same be taken into account by creating new ways to protect communications and data.

It remains to find the best solutions. This is the problem that attempts to answer the National Institute of Standards and Technology (NIST), the American Institute of Standards and Technology, which designates protocols that should resist the quantum computer. The aim is to set new standards.

Anssi recommends post-quantum cryptography
For Anssi, post-quantum cryptography (Post-Quantum Cryptography, PQC) is “the most promising way to thwart the quantum threat“. It’s about a “family of cryptographic algorithms” including “the establishment of digital keys and signatures“who assure”security (…) even against an attacker equipped with quantum computers“. These algorithms can be run on classic computers with traditional communication channels. They can therefore be deployed in advance on existing infrastructure, notes Anssi in its opinion. Be careful though, she specifies that she will not approve any direct replacements algorithms currently used in the short/medium term because the PQC is still too immature.

On the other hand, the Agency considers that quantum key distribution (Quantum Key Distribution, QKD) does not constitute “the natural evolutionary path of secure communications“. This is a family of methods based on physical principles, and not mathematics as is the case for usual cryptography. It allows two correspondents to build “a common secret” (one key) while chatting on public channels. Two “canals” are thus necessary: ​​a channel with controlled physical properties (an optical fiber or a direct link in the open air) without a device interacting with the information transported, and a classic network link. QKD is generally put forward to establish confidential and honest communicationsi.e. not modifiable by an attacker.

The QKD is therefore completely dependent on the physical characteristics of the channels which it borrows, which makes its large-scale deployment “complex and expensive“, judges Anssi. Moreover, in the absence of a direct line connecting two points wishing to negotiate a common key, users are led to negotiate”section keys” on a path made up of several nodes. However, this requires having confidence in these intermediaries. What constitutes “a major step backwards from current end-to-end key negotiation methods”, notes the authority. This technology may eventually be called upon to play a role in niche apps. she concludes.

Set up hybrid mechanisms
Protective measures must therefore already be put in place to protect the confidentiality of exchanges and data. Anssi recommends the adoption of so-called “hybrids“, combining “proven asymmetrical mechanisms” (vulnerable to attacks performed by a quantum computer) with “asymmetric mechanisms“supposedly resistant to the quantum computer. System developers in front of protect information beyond 2030 should consider the adoption of such measures and prepare the means toa migration of their cryptographic mechanisms, concludes Anssi.

These recommendations will affect the delivery security visas. Anssi explains that it will adapt its evaluation methods. The final phase, in which the agency will issue security visas claiming long-term pre-quantum and post-quantum security assurance with optional hybridization, is highly dependent on advances in research. The specifics of this phase will be adapted over the next few decades, specifies the authority.

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Cybersecurity: Anssi seriously anticipates the quantum threat and will adapt its visas

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