However, he had been unable to come up with a better solution. Luke Jr. proposed an encoding method that could be used to deploy SW without a disruptive flag day. This method defined a new scriptPubkey type similar to P2SH and required the scriptsig for this scriptPubkey to be empty during the soft-fork. Signatures were not covered under txid but carried alongside and then committed to in blocks in a separate hashtree. The approach used in elements alpha did not disrupt the normal relay handling process, whereas this approach would require a different hash or a separate mechanism for witness transport.