Patent ID: 7715556
Filing Date: 2010-05-11
Classification: H04L

Abstract:
1. A key establishment method comprising: (a) a server defining a set of linear functions which use elements of a first finite field as coefficients and satisfy a commutative rule, selecting a first linear function from the set, and selecting a predetermined element from a second finite field; (b) the server, for each of a plurality of nodes, selecting a second linear function from the set; generating a combination function based on the first linear function and the second linear function of the corresponding node; generating a value of the second linear function of the corresponding node using the selected element as a factor; and transmitting the combination function and the value of the second linear function to the corresponding node; and (c) each node exchanging the value of the second linear function received from the server with the other nodes, computing a value of the combination function using the exchanged value as a factor, and establishing the computed value as a shared key among the nodes wherein (b) comprises generating the combination function ƒ∘h and transmitting the combination function ƒ∘h i (x)mod(x 2 −x) and the value h i (α) of the second linear function to each node.