Patent ID: 8848921

Claim:
A group key management method, comprising: selecting, by a group controller, a mapping field f and a finite field F for use by a group in communication with the group controller, wherein the group has n group members; receiving, by the group controller, a m-dimensional private vector from each group member via a secure channel; assigning and sending, by the group controller, a serial number to each group member, wherein m and n are positive integers, and 2≦m≦n; randomly selecting, by the group controller, a mapping parameter in the finite field F; mapping, by the group controller, the private vectors of all the group members into a new set of vectors in a vector space using the mapping f according to the mapping parameter, wherein if the set of vectors is linearly dependent the mapping parameter is reselected to perform remapping or the step of selecting is repeated to allow each group member to reselect a private vector, until the new set of vectors is linearly independent; selecting, by the group controller, a random number in the finite field F as a group key; constructing, by the group controller, a system of linear equations using the new set of vectors and the group key; computing, by the group controller, a unique solution of the system of linear equations defined as a central vector; and broadcasting or multicasting, by the group controller, the central vector and the mapping parameter to all the group members via an open channel, wherein after the group members receive the central vector and the mapping parameter, the private vector of each group member is mapped to a new vector in the vector space according to the mapping parameter, and the group key is obtained by calculating the inner product of the new vector and the central vector.