Description
Date depot: 16 juillet 2019
Titre: Secure Symmetric Primitives and the Post-Quantum World
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 ofthe induced breakthrough in computational power. Cryptology is one of the affected disciplines. Indeed, the current state-of-the-art asymmetric cryptographywould become insecure, and we are actively searching for alternatives. Symmetric cryptography, essential for enabling secure communications, seems much lessaffected at first sight: its biggest known threat is Grover’s algorithm, which allows exhaustive key searches in the square root of the normal complexity. Thus, sofar, it is believed that doubling key lengths suffices to maintain an equivalent security in the post-quantum world. The security of symmetric cryptography iscompletely based on cryptanalysis: we only gain confidence in the security of a symmetric primitive through extensive and continuous scrutiny. It is thereforenot possible to determine whether a symmetric primitive might be secure or not in a post-quantum world without first understanding how a quantum adversarycould attack it. Correctly evaluating the security of symmetric primitives in the post-quantum world cannot be done without a corresponding cryptanalysistoolbox, which neither exists nor has ever been studied. Next, doubling the key length is not a trivial task and needs to be carefully studied. With the help ofthis toolbox, the cryptographic community should propose efficient solutions to ensure security in the post-quantum world. This will help prevent the chaos thatbig quantum computers would generate: being ready in advance will definitely save a great amount of time and money, while protecting our current and futurecommunications. Therefore, an important challenge to solve is to redesign symmetric cryptography for the post-quantum world. Due to environmental constraints, it is verylikely that common users will never take advantage of quantum capabilities, buta powerful adversary will. It is therefore vital that we dispose of primitives thatare efficient on classical computers and secure against quantum adversaries. Thismeans that we have definitely a lot of work to do with respect to symmetriccryptography. This PhD will contribute to fill this gap. Theaim of this toolbox is two-fold: 1) analyze existing cryptosystems/primitives, and2) design new ones which will give us confidence in the post-quantum world.
Doctorant.e: Florez Gutierrez Antonio