hash函数的特性：即任意大小的信息经hash函数变换后都能形成（）长度的“摘要”。

A．you’re not be authorized.
B．either the web page no longer exists on the server or it is nowhere to be found.
C．the web server is busy.
D．all are true.

A．electronics commerce
B．electronic contract
C．electronic commerce
D．electron commerce