The Random Oracle Model Instantiation Research And Applications

Random oracle model methodology is introduced by Bellare and Rogaway in the middle of 1990's. There's a greatly growing appreciation of provable security in practice with this methodology. A few years ago provable security was largely known only to theorecticians. It clarifies what the provable security is, explains some basic notions involved in the theory of provable security and illustrates the basic idea of random oracle model.There is a kind of schemes that is secure in the random oracle model, but broken after instantiation, that appeared in Canetti and Goldreich's research. It is stressed that the secutiry of final schemes depends on the independence of the hash functions which are to be used to instantiate the oracles of the schemes. So far there's no clear defition about "Independent". It provides a theorem to distinguish whether a protocol is depending on the hash function. With this theorem it comes to the conclusion that there are flaws in the examples used in Canetti and Goldreich's example. And the proof presented in Canetti and Goldreich's research that there's no good instantiation by single polynomial-time function is insufficient.Threshold signature scheme is devised by Desmedt and Franklewith the base of secret-sharing that is sponsored by Shamir. A new traceable (t, n) threshold signature scheme is proposed with a new modified ElGamal signature scheme. The new threshold signature scheme is secure in the random oracle model. The identities of signers can be revealed recurring to the trusted key authentication center when it is necessary.