Searching Keyword Using Public-Key Ciphertexts with Hidden Structures

Searching as fast as possible without sacrificing semantic security of the encrypted s using Searchable Public-key Ciphertexts with Hidden Structures (SPCHS). In this all searchable ciphertexts are structured by hidden relations, and with trapdoor corresponding to a, search algorithm provide guidance to find all matching ciphertexts efficiently. Construct SPCHS from scratch in which ciphertexts have a hidden star like structure. It is semantically secure in the Random Oracle (RO) Model. Search complexity is depends on the actual number of ciphertexts containing queried rather than the number of all ciphertexts. Finally we propose, Generic SPCHS is constructed from Identity Based Encryption (IBE) and collision-free full-identity malleable Identity Based Key Encapsulation Mechanism (IBKEM). In this collision-free full-identity malleable IBKEM instances are semantically secure and anonymous in the RO and standard models.