Zero-knowledge proof is a very interesting problem in modern cryptography, which attracts the attention of many cryptographers, and there are plenty of researches. It is one of the hot research field in cryptography. First, we made a simple introduction of zero-knowledge proof. Then we had given a perfect quantum zero knowledge proof system on a specific NP… (More)
In this paper we classify finite groups whose nonnormal subgroups are of order p or pq, where p, q are primes. As a by-product, we also classify the finite groups in which all nonnormal subgroups are cyclic.