Method for enhancing the security of the multicast or broadcast system

A method for enhancing security of a broadcast or multicast system, wherein, after defining by a base station system parameters of the broadcast/multicast system, the method comprises:

• receiving by the base station a registration request message from a mobile terminal, the registration request message contains device identity information of the mobile terminal;
• and
• registering by the base station the mobile terminal according to the registration request message and transmitting by the base station an authorized key to the mobile terminal upon successful registration,
• wherein, the method further comprises:
• receiving by the mobile terminal a broadcast/multicast encryption text transmitted from the base station, wherein, the mobile terminal decrypts the broadcast/multicast encryption text with the authorized key,
• wherein, an operation of defining by a base station system parameters of the broadcast/multicast system comprises:
• defining two q-order cyclic groups of (G1, +) and (G2, ·), wherein, q is a prime number, G1 is irreversible in Diffie-Hellman calculation, and P is a generator of G1;
• defining e representing bilinear transformation on G1 and G2;
• and defining h(·) representing a unidirectional hash function,
• wherein, an operation of registering by the base station the mobile terminal according to the registration request message comprises:
• verifying, by the base station, physical information of the mobile terminal, and when the mobile terminal complies with the registration request message, selecting by the base station randomly a number n−1 of different elements from Z*q, wherein, n is an integer larger than or equal to 2, and selecting from G1 and publishing two elements Q1 and Q2;
• constructing randomly an (n−1)-order secret polynomial f(x)εZp[x];
• calculating QK from QK=f(0)PεG1 and Vi from Vi=f(vi)P(i=0, 1, . . . , n−2) according to a constructed polynomial, wherein, i ranges from 0 to n−2;
• and extracting the device identity information IDx from the registration request message, and calculating Vx from Vx=f(IDx)(Q1+Q2) according to the device identity information IDx.