HEAD: Hybrid encryption with delegated decryption capability

Abstract

We consider the problem of adding the functionality of delegated decryption on top of usual encryption schemes. An appropriate security model is described for such schemes. Our main contribution is to present a practical and efficient public key encryption scheme HEAD, which achieves the functionality of delegated decryption. The new scheme is obtained by combining bilinear map based techniques with Kurosawa-Matsuo modification of DRIES. The scheme HEAD is proved to be secure based on appropriate security assumptions on the components. © Springer-Vorlag 2004.