Applied Algebra Group at the University of Zürich


Structured codes with cryptographic applications

Paolo Santini's talk
Date: 07.11.18   Time: 16.00 - 17.00   Room: Y27H12

Code-based cryptosystems are among the oldest and still unbroken public-key primitives. Due to their intrinsic resistance against quantum attacks, code-based cryptosystems are also among the most promising candidates for the post quantum world. The main drawback of these systems is represented by the relatively large dimensions of the public keys; this is one of the reasons why, until now, code-based cryptosystems have not encountered the same success of other solutions (like RSA). One of the most established ways to address this issue consists in using quasi-cyclic (QC) low-density parity-check (LDPC) codes, that are non-algebraic codes characterized by sparse parity-check matrices whose rows are all identical up to a cyclic shift. In this talk it will be shown how these codes can be used in public key-cryptosystems and their main properties and drawbacks will be described. Furthermore, the family of reproducible codes will be presented, that are codes characterized by a compact representation. QC codes represent just a particular case of this general framework, thus opening up for a variety of different solutions in code-based cryptography.