International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Patrick Felke

Publications

Year
Venue
Title
2021
PKC
Analysis of Multivariate Encryption Schemes: Application to Dob 📺
In this paper, we study the effect of two modifications to multivariate public key encryption schemes: internal perturbation (ip), and Q_+. Focusing on the Dob encryption scheme, a construction utilising these modifications, we accurately predict the number of degree fall polynomials produced in a Gröbner basis attack, up to and including degree five. The predictions remain accurate even when fixing variables. Based on this new theory we design a novel attack on the Dob encryption scheme, which breaks Dob using the parameters suggested by its designers. While our work primarily focuses on the Dob encryption scheme, we also believe that the presented techniques will be of particular interest to the analysis of other big-field schemes.
2004
CHES
2003
PKC