A method for secure key agreement among a subset of a plurality of transceivers includes generating a first ordered subset of a plurality of keys kλj, where j=0 to S. Each of the subset of the plurality of transceivers may possess at least one of the plurality of keys kλj from the first ordered subset. Each of the subset of the plurality of transceivers possessing one or more keys kλi, i=1 to S, also possesses at least one key from a second ordered subset of the plurality of keys kλj, j=0 to i−1. A key with index λ0 is designated as a group key. A binary sum of the group key kλ0 and a key kλj, where j≠0, is transmitted from one or more of the subset of the plurality of transceivers that possesses the group key kλ0.