Matrix powers algorithms for trust evaluation in PKI architectures

TL;DR

This paper introduces a novel polynomial matrix algorithm leveraging linear algebra for trust evaluation in PKI networks, offering optimized computation and applicability to complex graph structures with cycles.

Contribution

The paper presents a new matrix-based algorithm for trust assessment in PKI, improving efficiency and handling cyclic trust graphs compared to previous graph-based methods.

Findings

Algorithm efficiently computes trust over all paths.

Applicable to graphs with cycles, enhancing trust evaluation.

Accelerates cross-certificate validation processes.

Abstract

This paper deals with the evaluation of trust in public-key infrastructures. Different trust models have been proposed to interconnect the various PKI components in order to propagate the trust between them. In this paper we provide a new polynomial algorithm using linear algebra to assess trust relationships in a network using different trust evaluation schemes. The advantages are twofold: first the use of matrix computations instead of graph algorithms provides an optimized computational solution; second, our algorithm can be used for generic graphs, even in the presence of cycles. Our algorithm is designed to evaluate the trust using all existing (finite) trust paths between entities as a preliminary to any exchanges between PKIs. This can give a precise evaluation of trust, and accelerate for instance cross-certificate validation.