Two new constructions of chosen-ciphertext secure fuzzy identity-based encryption (fuzzy-IBE) schemes without random oracle are proposed. The first scheme combines the modification of chosen-plaintext secure Sahai a...Two new constructions of chosen-ciphertext secure fuzzy identity-based encryption (fuzzy-IBE) schemes without random oracle are proposed. The first scheme combines the modification of chosen-plaintext secure Sahai and Waters' "large universe" construction and authenticated symmetric encryption, and uses con- sistency checking to handle with ill-formed ciphertexts to achieve chosen-ciphertext security in the selective ID model. The second scheme improves the efficiency of first scheme by eliminating consistency checking. This improved scheme is more efficient than existing chosen-ciphertext secure fuzzy-IBE scheme in the standard model.展开更多
基金the National High Technology Research and Development Program (863) of China(No. 2006AA12A106)
文摘Two new constructions of chosen-ciphertext secure fuzzy identity-based encryption (fuzzy-IBE) schemes without random oracle are proposed. The first scheme combines the modification of chosen-plaintext secure Sahai and Waters' "large universe" construction and authenticated symmetric encryption, and uses con- sistency checking to handle with ill-formed ciphertexts to achieve chosen-ciphertext security in the selective ID model. The second scheme improves the efficiency of first scheme by eliminating consistency checking. This improved scheme is more efficient than existing chosen-ciphertext secure fuzzy-IBE scheme in the standard model.