[BA] Survey on Randomness Homomorphic Commitment Schemes

Geb. 50.34, Raum 252 oder online https://i62bbb.tm.kit.edu/b/mic-7xx-rfr

2024-07-23

Simon Wülker

15:45

Commitment schemes are an important cryptographic primitive that allow a committer to decide on a hidden value and possibly reveal later. They are commonly used for zero knowledge proofs and other protocols like secure coin flipping.
Among them, rerandomizable commitment schemes are of special interest due to their potential to mitigate randomness subversion attacks. Homomorphic commitment schemes allow for easy rerandomization by combining a potentially subverted commitment with a "fresh" one, without modifying the message itself. Despite this, little research has been done to survey the available options for implementors.

In this work, we present a list of five practical randomness-homomorphic commitment schemes from recent publications in the field along with proofs of their security. We study their constructions in detail and compare them in terms of both the security they provide and their performance. The presented schemes depend on the hardness of problems from different domains, including the discrete logarithm problem and well known lattice problems like the Short Integer Solution and Learning with Errors problems. Finally, we give recommendations about the applications of the presented schemes.