Author(s)

D. Gligoroski, S. J. Knapskog & S. Andova

Abstract

By means of a recently proposed encryption and error correcting system we define schemes for building secure protocols for a number of different scenarios for management of digitally produced documents. The documents are both encrypted and robust against a certain amount of intentional or non-intentional errors. Some of the schemes are based on the property of the system that the introduced redundant information needed for error-correction is not algorithmically predetermined but can arbitrarily be chosen, i.e. it can be given a semantical meaning if necessary or if desired by the user. Keywords: secure documents, error-correction, cryptography, quasigroup, quasigroup string transformations. 1 Introduction Building methods that can deal with errors in presence of cryptographic operations is not new. Many of them combine encryption and encoding in various ways, depending for what problems they are intended to solve. For instance, there are several methods developed in biometrics, for use and protection of biometric data, as well as methods for a cryptographic protection of digitally produced documents. For example, Ray and Ellson [1] in 1994 registered a US patent, based on a combination of cryptographic and error-correction techniques; the method solves the problem of credit card authentication and is based on use of biometric data extracted from an image of the card holder. O’Gorman and Rabinovich in several works [2, 3, 4] from 1996-1998 used also a combination of cryptographic

Keywords

secure documents, error-correction, cryptography, quasigroup, quasigroupstring transformations.