BIKE and its Relation to Lattices over Polynomial Rings
Talk by Michael Schaller
Date: 23.10.24 Time: 16.30 - 17.30 Room:
In this talk we study the BIKE cryptosystem. We will introduce a lattice over a polynomial ring which we construct from the public key. The private key is a vector in this lattice with special properties (being sparse). We study the properties of this lattice. Furthermore, using this framework we will reformulate a previous work about weak keys for BIKE in terms of this lattice and show that their weak keys correspond to shortest vectors in this rank 2 lattice. Instead of only finding the shortest vector, we are able to construct a reduced basis and generalize their attack. We also propose new problems which arise from the reformulation of their attack in terms of lattices.