This paper discusses the design, implementation, and deployment of a secure and practical payment system for electronic commerce on the Internet. The system is based on the iKP family of protocols-(i=1,2,3)-developed at IBM Research. The protocols implement credit card-based transactions between buyers and merchants while the existing financial network is used for payment clearing and authorization. The protocols are extensible and can be readily applied to other account-based payment models, such as debit cards. They are based on careful and minimal use of public-key cryptography, and can be implemented in either software or hardware. Individual protocols differ in both complexity and degree of security. In addition to being both a precursor and a direct ancestor of the well-known SET standard, iKP-based payment systems have been in continuous operation on the Internet since mid-1996. This longevity-as well as the security and relative simplicity of the underlying mechanisms-makes the iKP experience unique. For this reason, this paper also reports on, and addresses, a number of practical issues arising in the course of implementation and real-world deployment of a secure payment system.

Security in link-state routing protocols is a feature that is both desirable and costly. This paper examines the cost of security and presents two techniques for efficient and secure processing of link state updates. The first technique is geared towards a relatively stable internetwork environment while the second is designed with a more volatile environment in mind.

This paper discusses issues and idiosyncrasies associated with changing passwords and keys in distributed computer systems. Current approaches are often complicated and fail to provide the desired level of security and fault tolerance. A novel and ve

Licensing is a topic of increasing importance for software publishers and users. More and more, the magnitude of financial transfers between these two partners are determined by some electronic licensing service being part of the system on which the licensed software is running. In order to ease the use and management of such licensing schemes and to enable economic software usage in enterprise-wide computer systems through flexible and fair billing structures, various organizations are working on formulating requirements, defining architectures, and building standard interfaces for so called license brokerage systems. The trustworthiness of these services is essential because large amounts of money can depend on them. Most of these licensing services are currently operating independently of access control and rely on proprietary and unpublished security algorithms. This paper proposes an extension of access control to integrate licensing called Stateful Access Control and it addresses some aspects of virus protection.