Mathematical Foundations of Computer Security

Using digital certificates for authorization by proxy in OS Linux

V. I. Ryzhkov

Tomsk State University, Tomsk

Abstract: In this paper, a solution for delegation of some set of rights from one user (delegator) to another (proxy user) for a fixed time period is proposed. For this goal, it is offered to use “proxies”. “Proxy” is an object containing the following fields: delegator's identifier, proxy user's identifier, time period (set by delegator), list of delegated rights, and delegator's digital signature. This solution is implemented for OS Linux using OpenSSL cryptographic toolkit and pluggable authentication modules (PAM). The object “proxy” is designed as X.509 v3 certificate, and the delegated rights are specified at the field of certificate extensions. Authorization by proxy is implemented as PAM module.

Keywords: electronic certificates, X.509, Linux, PAM, OpenSSL, authorization by proxy.

UDC: 004.94