Here, ???11??? of A???B means the concatenation of data A and data B. Also, the hash function is a function which outputs data of a fixed length, for example, 64 bits or 128 bits, with respect to input data of an arbitrary length, and is a function such that, when y(=hash (x)) is given, determination of x is difficult and determination of the set of x1 and x2 in which hash (x1)=hash (x2) is also d