Non-interactive Threshold Cryptosystems Secure Against Chosen Ciphertext Attacks in the Standard Model
Qixiang Mei, HE Da-ke · Dianzi xuebao · 2005
Two threshold cryptosystems secure against chosen ciphertext attacks are proposed.The ciphertext in the first system is the resulting of applying the Canetti-Halevi-Kazt approach to the Boneh-Boyen Identity-Based Encryption scheme.While,in the second system,the ciphertext is essentially the same as that in the Waters IBE scheme except that theidentityhere is the hash of the first two parts of the ciphertext.Since the servers can publicly verify the ciphertext validity before providing the decryption shares and the shares can be publicly verified by the combiner,both the schemes achieve the non interactivity.The security in both the proposals is proved under the standard Decisional Bilinear Diffie-Hellman assumption.