George I. Davida

A database encryption system with subkeys

A new cryptosystem that is suitable for database encryption is presented. The system has the important property of having subkeys that allow the encryption and decryption of fields within a record. The system is based on the Chinese Remainder Theorem.

Hiding the Hidden: A software system for concealing ciphertext as innocuous text

In this paper we present a system for protecting the privacy of cryptograms to avoid detection by censors. The system transforms ciphertext into innocuous text which can be transformed back into the original ciphertext. The expandable set of tools allows experimentation with custom dictionaries, automatic simulation of writing style, and the use of Context-Free-Grammars to control text generation. The scope of this paper is to provide an overview of the basic transformation processes and to demonstrate the quality of the generated text.

Anonymity Control in E-Cash Systems

Electronic cash, and other cryptographic payment systems, offer a level of user anonymity during a purchase, in order to emulate electronically the properties of physical cash exchange. However, it has been noted that there are crime-prevention situations where anonymity of notes is undesirable; in addition there may be regulatory and legal constraints limiting anonymous transfer of funds. Thus pure anonymity of users may be, in certain settings, unacceptable and thus a hurdle to the progress of electronic commerce.

Division in logspace-uniform NC1

Beame, Cook and Hoover were the first to exhibit a log-depth, polynomial size circuit family for integer division. However, the family was not logspace-uniform. In this paper we describe log-depth, polynomial size, logspace-uniform, i.e. , NC 1 circuit family for integer division. In particular, by a well-known result this shows that division is in logspace. We also refine the method of the paper to show that division is in dlogtime-uniform NC 1 .

Fast parallel arithmetic via modular representation

An almost uniform

Optimum Featurs and Graph Isomorphism

NC^1

O(log(n)) Parallel Time Finite Field Inversion

circuit family for integer division is presented. The circuit size is

Protecting Shared Cryptographic Keys

O(n^6 / \log (n))

Forward-Error Correction with Decision Feedback*

. The circuit design is based on modular representation for integers below

Fast arithmetics using Chinese remaindering

2^n