Multisignatures
A multisignature is similar to a threshold signature, but does not hide the set of signers. In a weighted multisignature there are n public keys with weights assigned to each key. The signature is valid if produced by a subset of the keys whose weights exceed a specified threshold. One goal of multisignatures is compactness, meaning that the multisignature generated by t-of-n keys should be much shorter than t independent signatures (otherwise they are trivial to construct).