Paper 2018/1100

Correction to "Improving the DGK comparison protocol"

Thijs Veugen

Abstract

At the IEEE Workshop on Information Forensics and Security in 2012, Veugen introduced two ways of improving a well-known secure comparison protocol by Damgård, Geisler and Krøigaard, which uses additively homomorphic encryption. The first new protocol reduced the computational effort of one party by roughly $50\%$. The second one showed how to achieve perfect security towards one party without additional costs, whereas the original version with encrypted inputs only achieved statistical security. However, the second protocol contained a mistake, leading to incorrect outputs in some cases. We show how to correct this mistake, without increasing its computational complexity.

Note: This is a correction of a previous paper.