An investigation into soft-state protocol parameters

This paper addresses an approach of improving the consistency in soft-state based systems. The consistency in such a system is affected by many parameters; some are given by the environment while others are tunable. The environment parameters are the loss probability and latency of the channel between the endpoints, and the change rate of the source state.The tunable parameters are the refresh period and timeout period. We study how to specify the refresh and timeout periods as functions of the other parameters and evaluate whether such functions are useful to improve the system consistency. To that end, we performed simulation experiments with different parameter values and we investigated the relationship between them. Our results show that the consistency of a system using the timeout period based on the proposed function increases significantly, especially when used in a lossy environment. As for the refresh period, our results show that the lowest inconsistency is achieved when the refresh period is about the same as the channel latency

Cryptcoding : encryption and error-correction coding in a single step

In this paper we re-open a 25 years old question of joint encryption and error-correction coding, named here as Cryptcoding. Cryptcoding is a procedure in which encryption/decryption and error-correction coding/decoding are performed in a single step. We discuss the advantages of this approach over the traditional First-Encrypt-Then-Encode approach. To our knowledge only three different realizations of cryptcoding can be found in literature: the McEliece's public key encryption system using Goppa codes, the Kak's joint encryption and error-correction coding using D-sequences and the recently developed quasigroup random error-correcting codes. We briefly discuss the first two and mainly focus on the last one. We give two examples in which cryptcoding is efficiently employed for secure documentmanagement

Service discovery mechanisms : two case studies

Connecting other devices than workstations to the Internet is becoming commonplace now. In this article we investigate two approaches to the discovery Of devices and the services they may provide, viz., the Universal Plug 'n Play standard by Microsoft and the wireless Corba model