Responding to policies at runtime in TrustBuilder

Abstract

Automated trust negotiation is the process of establishing trust between entities with no prior relationship through the iterative disclosure of digital credentials. One approach to negotiating trust is for the participants to exchange access control policies to inform each other of the requirements for establishing trust. When a policy is received at runtime, a compliance checker determines which credentials satisfy the policy so they can be disclosed. In situations where several sets of credentials satisfy a policy and some of the credentials are sensitive, a compliance checker that generates all the sets is necessary to insure that the negotiation succeeds whenever possible. Compliance checkers designed for trust management do not usually generate all the satisfying sets. In this thesis, we present two practical algorithms for generating all satisfying sets given a compliance checker that generates only one set. The ability to generate all of the combinations provides greater flexibility in how the system or user establishes trust. For example, the least sensitive credential combination could be disclosed first. These ideas have been implemented in TrustBuilder, our prototype system for trust negotiation.

TrustBuilder2: A Reconfigurable Framework for Trust Negotiation

“…During our experiments, the client process spent, on average, 226 ms interacting with the compliance checker during a single trust negotiation. The complexity of the compliance checking process has also been observed in other, independent trust negotiation implementations (e.g., see [23]). This suggests that a novel and highly-effective denial of service attack against trust negotiationenabled services is to force the use of the remote party's compliance checker.…”

XeNA: an access negotiation framework using XACML

“…The typical setup is that someone or a process wants to perform some action on a resource. Therefore, a request is sent (2) to the component that actually protects that resource (like a filesystem or a Web server), called a Policy Enforcement Point (PEP). The PEP will form a request, in its native request format, based on the requestor's attributes, the resource in question, the action, and other information pertaining to the request.…”

“…In [1][2][3], authors suggest a prototype for trust establishment called TrustBuilder. It allows negotiating trust across organizational boundaries, between entities from different security domains.…”

Automated Trust Negotiation in Autonomic Environments

“…IBM specified the Trust Policy Language for a role based access control scheme that uses credentials to determine which roles a principal can obtain. TrustBuilder [12] uses this language to implement a trust negotiation system that incorporates trust reputation measures. PeerTrust [10] is an ATN system that can handle X.509 certificates and import RDF for its policies.…”

“…However, the draft neglects the protection of sensitive information during the negotiation and requires session state at the participating hosts. The research on Automated Trust Negotiation (ATN) [14] [12] [2] deals with automatically establishing mutual trust between strangers by an iterative credential exchange. Automated Trust Negotiation systems use a policy driven iterative negotiation process to reach an agreement between two parties that need not have a prior trust relationship.…”