Projet de recherche doctoral numero :5550


Date depot: 20 décembre 2018
Titre: Symmetric Primitives in the Post-Quantum World
Encadrant : André CHAILLOUX (Inria-Paris (ED-130))
Directrice de thèse: Maria NAYA PLASENCIA (Inria-Paris (ED-130))
Domaine scientifique: Sciences et technologies de l'information et de la communication
Thématique CNRS : Non defini

Resumé: As years go by, the existence of quantum computers becomes more tangible and the scientific community is already anticipating the enormous consequences of the induced breakthrough in computational power. Cryptology is one of the affected disciplines. Indeed, the current state-of-the-art asymmetric cryptography would become insecure, and we are actively searching for alternatives. Symmetric cryptography, essential for enabling secure communications, seems much less affected at first sight: its biggest known threat is Grover’s algorithm, which allows exhaustive key searches in the square root of their classical complexity. Thus, so far, it is believed that doubling key lengths suffices to maintain an equivalent security in the post-quantum world. The security of symmetric cryptography is completely based on cryptanalysis: we only gain confidence in the security of a symmetric primitive through extensive and continuous scrutiny. It is therefore not possible to determine whether a symmetric primitive might be secure or not in a post-quantum world without first understanding how a quantum adversary could attack it. Correctly evaluating the security of symmetric primitives in the post-quantum world cannot be done without a corresponding cryptanalysis toolbox, which has only recently started to be studied. Next, doubling the key length is not a trivial task and needs to be carefully studied. The cryptographic community should propose efficient solutions secure in the post-quantum world with the help of the previously mentioned quantum symmetric cryptanalysis toolbox. This will help prevent the chaos that big quantum computers would generate: being ready in advance will definitely save a great amount of time and money, while protecting our current and future communications.

Doctorant.e: Schrottenloher Andre