Discrete logarithm problem in some families of sandpile groups
This work addresses cryptographic vulnerabilities in graph-based cryptosystems, but it is incremental as it extends prior results to non-cyclic groups and new graph types.
The paper tackles the discrete logarithm problem in sandpile groups of specific graph families, showing that the problem is efficiently solvable in cases like square cycle graphs, wheel graphs, and subdivided banana graphs, often by exploiting known generators or pseudoinverse properties.
Biggs proposed the sandpile group of certain modified wheel graphs for cryptosystems relying on the difficulty of the discrete logarithm problem. Blackburn and independently Shokrieh showed that the discrete logarithm problem is efficiently solvable. We study Shokrieh's method in cases of graphs such that the sandpile group is not cyclic, namely the square cycle graphs and the wheel graphs. Knowing generators of the group or the form of the pseudoinverse of the Laplacian matrix makes the problem more vulnerable. We also consider the discrete logarithm problem in case of the so-called subdivided banana graphs. In certain cases the sandpile group is cyclic and a generator is known and one can solve the discrete logarithm problem without computing the pseudoinverse of the Laplacian matrix.