Paper 2006/034

Direct Chosen-Ciphertext Secure Identity-Based Key Encapsulation without Random Oracles

Eike Kiltz and David Galindo

Abstract

We describe a new and practical identity-based key encapsulation mechanism that is secure in the standard model against chosen-ciphertext (CCA2) attacks. Since our construction is direct and not based on hierarchical identity-based encryption, it is more efficient than all previously proposed schemes. Furthermore, we give the first chosen-ciphertext secure identity-based key encapsulation mechanism with threshold key delegation and decryption in the standard model.