Université de Liège
In this paper, the authors propose a new way to deal with the problem of message encoding, which offers several advantages though some disadvantages. Their scheme is based on a quite simple combination of the standard elgamal scheme with a message encoding inspired by the naccache-stern cryptosystem. They consider their solution as a new step towards the open problem of designing a discrete-logarithm based encryption scheme with the property of being additively homomorphic. Unfortunately, their construction is still not a complete solution. They hope however that it might give clues for a possible full solution.