Catálogo de publicaciones - libros

A public-key cryptosystem is usually used for key management, in particular to session key management. The paper presents a method for handling a batch of concurrent keys with homomorphic public-key cryptosystems such as RSA, Paillier and ElGamal. Theorematically, regardless Shacham and Boneh proved that it is impossible to provide batch RSA encryption of messages with a single certificate, the present result is positive when the messages are small. Practically, the present method is compliant to the de facto standard SSL/TLS handshake and increases the SSL system performance.

Enterprises use security equipments in order to protect their information assets from various attacks such as viruses and hacking. However, such individual equipments hardly provide enterprise level integrated security. Recently, there has been a great need in small/medium businesses to purchase such integrated security services in a cost effective way by means of an ASP solution. We propose the architecture of a web-based enterprise security manager that can be used as an ASP solution. To the best of our knowledge, it is the first such system that provides integrated security management services through the web. We conducted experiments on our prototype system, and showed that it could handle 30 million logs per day, and serve 300 concurrent web users with 20 transactions per session. This system is now running as a commercial application service at KT Bizmeka, which is one of the largest Korean ASPs.

A fingerprinting code is a set of codewords that are embedded in each copy of a digital object with the purpose of making each copy unique. If the fingerprinting code is c -secure with ε error, then the decoding of a pirate word created by a coalition of at most c dishonest users, will expose at least one of the guilty parties with probability 1– ε . The Boneh-Shaw fingerprinting codes are n -secure codes with ε error, where n also denotes the number of authorized users. Unfortunately, the length the Boneh-Shaw codes should be of order O ( n ^3log( n / ε )), which is prohibitive for practical applications. In this paper, we prove that the Boneh-Shaw codes are ( c < n )-secure for lengths of order O ( nc ^2log( n / ε )). Moreover we show how to use these codes to construct binary fingerprinting codes with length L = O ( c ^6log c log n ), with probability of error O (1/ n )= exp (–Ω( L )), and identification algorithm of complexity poly (log n )= poly ( L ). These results improve in some aspects the best known schemes and with a much more simple construction.