PKI Scalability Issues

This report surveys different PKI technologies such as PKIX and SPKI and the issues of PKI that affect scalability. Much focus is spent on certificate revocation methodologies and status verification systems such as CRLs, Delta-CRLs, CRS, Certificate Revocation Trees, Windowed Certificate Revocation, OCSP, SCVP and DVCS.Comment: 23 pages, 2 figure

Simple Public Key Infrastructure Analysis Protocol Analysis and Design

Secure electronic communication is based on secrecy, authentication and authorization. One means of assuring a communication has these properties is to use Public Key Cryptography (PKC). The framework consisting of standards, protocols and instructions that make PKC usable in communication applications is called a Public Key Infrastructure (PKI). This thesis aims at proving the applicability of the Simple Public Key Infrastructure (SPKI) as a means of PKC. The strand space approach of Guttman and Thayer is used to provide an appropriate model for analysis. A Diffie-Hellman strand space model is combined with mixed strand space proof methods for proving the correctness of multiple protocols operating in the same context. The result is the public key mixed strand space model. This model is ideal for the analysis of SPKI applications operating as sub-protocols of an implementing application. This thesis then models the popular Internet Transport Layer Security (TLS) protocol as a public key mixed strand space model. The model includes the integration of SPKI certificates. To accommodate the functionality of SPKI, a new protocol is designed for certificate validation, the Certificate Chain Validation Protocol (CCV). The CCV protocol operates as a sub-protocol to TLS and provides online certificate validation. The security of the TLS protocol integrated with SPKI certificates and subprotocols is then analyzed to prove its security properties

KeyNote: Trust Management for Public-Key Infrastructures

This paper discusses the rationale for designing a simple trust-management system for public-key infrastructures, called KeyNote. The motivating principles are expressibility, simplicity, and extensibility. We believe that none of the existing public-key infrastructure proposals provide as good a combination of these three factors

SPADE: SPKI/SDSI for Attribute Release Policies in a Distributed Environment

Shibboleth is a federated administrated system that supports inter-institutional authentication and authorization for sharing of resources. SPKI/SDSI is a public key infrastructure whose creation was motivated by the perception that X.509 is too complex and flawed. This thesis addresses the problem of how users that are part of a Public Key Infrastructure in a distributed computing system can effectively specify, create, and disseminate their Attribute Release Policies for Shibboleth using SPKI/SDSI. This thesis explores existing privacy mechanims, as well as distributed trust management and policy based systems. My work describes the prototype for a Trust Management Framework called SPADE (SPKI/SDSI for Attribute Release Policies in a Distributed Environment) that I have designed, developed and implemented. The principal result of this research has been the demonstration that SPKI/SDSI is a viable approach for trust management and privacy policy specification, especially for minimalistic policies in a distributed environment

Greenpass RADIUS Tools for Delegated Authorization in Wireless Networks

Dartmouth\u27s Greenpass project extends how public key cryptography can be used to secure the wireless LAN with a RADIUS (Remote Authentication Dial In User Service) server that is responsible for handling authentication requests from clients (called supplicants in the 802.1x authentication model). This thesis describes the design and implementation of the authentication process of Greenpass, specifically what decisions are made in determining who is granted access and how a small modification of already existing protocols can be used to provide guest access in a way that better reflects how delegation of authority works in the real world. Greenpass takes advantage of the existing PKI to authenticate local Dartmouth users via X.509 identity certificates using EAP-TLS. We use the flexibility of SPKI/SDSI (Simple Public Key Infrastructure/Simple Distributed Security Infrastructure) authorization certificates to distribute the responsibility of delegating access to guests to certain authorized delegators, avoiding some of the necessary steps and paperwork associated with having a large centralized entity responsible for the entire institution. This thesis also discusses how our solution can be adapted to support different methods of guest delegation and investigates the possibility of eliminating the cumbersome central entity and administrative overhead traditionally associated with public key cryptography

Greenpass: Flexible and Scalable Authorization for Wireless Networks

Wireless networks break the implicit assumptions that supported authorization in wired networks (that is: if one could connect, then one must be authorized). However, ensuring that only authorized users can access a campus-wide wireless network creates many challenges: we must permit authorized guests to access the same network resources that internal users do; we must accommodate the de-centralized way that authority flows in real universities; we also must work within standards, and accommodate the laptops and systems that users already have, without requiring additional software or plug-ins. This paper describes our ongoing project to address this problem, using SPKI/SDSI delegation on top of X.509 keypair within EAP-TLS. Within the ``living laboratory\u27\u27 of Dartmouth\u27s wireless network, this project lets us solve real problem with wireless networking, while also experimenting with trust flows and testing the limits of current tools

Design and semantics of a decentralized authorization language

We present a declarative authorization language that strikes a careful balance between syntactic and semantic simplicity, policy expressiveness, and execution efficiency. The syntax is close to natural language, and the semantics consists of just three deduction rules. The language can express many common policy idioms using constraints, controlled delegation, recursive predicates, and negated queries. We describe an execution strategy based on translation to Datalog with Constraints, and table-based resolution. We show that this execution strategy is sound, complete, and always terminates, despite recursion and negation, as long as simple syntactic conditions are met