This is accomplished by several rounds of communication between the t+1 nodes. If one sends a bad message, then it is important that this node can be recognised, otherwise there is the possibility of a Dedicated Denial of Service Attack. GG20 solves this using an elegant property of the ECDSA algorithm, so that R, the part of the signature from a node can be used to query whether it was at fault (the 'bad actor'). Other features present in GG20 that increase efficiency are the ability to have Asynchronous Approval, where a large number of signatures can be pre-computed, calculating the R factor in the ECDSA signatures, before they are needed. This encompasses most of the computation and communication, with only the final round of communication necessary to actually sign the message, with all t nodes online at this stage. This means that for the bulk of the work, there is no longer the need for all nodes to be online simultaneously, with the implication that some network latency can be accommodated.