Using piecewise hashing and Lagrange interpolation polynomial to preserve electronic evidence

Abstract

Electronic evidence has some characteristics, such as it is easily deleted, modified, and fabricated, so it is presented to use piecewise hashing and Lagrange interpolation polynomial to preserve electronic evidence. On local computer, the electronic evidence is converted into the values of polynomials, and then these values are hided into images, finally they are uploaded to server. For finding erroneous pieces in electronic evidence, piecewise hashing techniques were used twice to verify the integrity of the evidence itself and the values of polynomials. On server side, the values of polynomials are extracted from the images, and all electronic data are recovered using Lagrange interpolation polynomial. Experiment results show that the method could reconstruct electronic evidence and guarantee its integrity, authenticity and validity even if the parts of evidence were destroyed or lost in network transmission. © 2011 Springer-Verlag.