Correcting a delegation protocol for grids

Delegation is one important aspect of large-scale distributed systems where many processes and operations run on behalf of system users and clients in order to achieve highly computational and resource intensive tasks. As such, delegation is often synonymous with the concept of trust, in that the delegator would expect some degree of reliability regarding the delegatee's ability and predictability to perform the delegated task. The delegation protocol itself is expected to maintain certain basic properties, such as integrity, traceability, accountability and the ability to determine delegation chains. In this paper, we give an overview of the vulnerabilities that one such delegation protocol exhibits, namely DToken, a lightweight protocol for Grid systems, as interesting examples of design mistakes. We also propose an alternative protocol, DToken II, which �fixes such vulnerabilities.