Patent ID: 8917870

Claim:
A method of computing a shared encryption key (k) for a group of n mobile devices, the group of n mobile devices comprising at least three mobile devices, wherein the method comprises, for an i-th mobile device of the group of n mobile devices: a hardware processor computing a public key (Xi) for the mobile device for transmission to at least one other mobile device of the group, wherein the public key (Xi) for the mobile device is a function of at least a shared password (π) known to all mobile devices of the group; the hardware processor computing a public value (Ki) for the mobile device for transmission to other mobile devices of the group, wherein the public value (Ki) for the mobile device is a function of at least a public key of another mobile device of the group that is also computed using the shared password (π); the hardware processor computing the shared encryption key (k) based upon public values of other mobile devices of the group, wherein each of the public values of other mobile devices of the group is a function of at least one other public key of at least one other mobile device of the group that is also computed using the shared password; and the hardware processor using the shared encryption key (k) to encrypt and decrypt subsequent communications with the at least one other device of the group.