AbstractThe paper describes some special aspects of the security infrastructure for distributed com- puting systems. Most heterogeneous and geographically dispersed distributed computing systems, e.g. GRID, use the Public Key Infrastructure (PKI). One of the main problem in such systems is the necessity to use time-limited proxy certificates for delegation of rights from user to an execution remote service which acts on behalf of the user. The problem is that there exists a contradiction between the limited lifetime of the proxy certificates and unpredictable time of the request processing. Our approach allows to avoid using the proxy certificates. This makes the security infrastructure of distributed computing systems simpler for developme...