Chosen-Ciphertext Secure Identity-Based Encryption in the Standard Model With Short Ciphertexts
The authors describe a practical identity-based encryption scheme that is secure in the standard model against chosen-ciphertext (IND-CCA2) attacks. Security is based on an assumption comparable to (but slightly stronger than) Bilinear Decisonal Diffie-Hellman (BDDH). A comparison shows that the construction outperforms all known identity-based encryption schemes in the standard model and its performance is even comparable with the one from the random-oracle based Boneh/Franklin IBE scheme. The proposed IBE scheme has furthermore the property that it fulfills some notion of "Redundancy-freeness", i.e. the encryption algorithm is not only a probabilistic injection but also a surjection.