Method of identifying invalid digital signatures involving batch verification by receiving digital messages, digital signatures, and signer identifiers, computing Z0 as a function of the received information, and determining if the digital signatures are valid. If so, stopping. If not, assigning a signature identifier to each digital signature, setting w equal to 1, computing Zw as a function of the received information and signature identifiers, and searching for a multiplicative relationship amongst Z0, Z1, . . . , Zw. If one is found then determining the invalid digital signatures from the multiplicative relationship and stopping. Otherwise, incrementing w and returning to the step of computing for additional processing if desired.