From kanzure at gmail.com Fri Feb 26 01:34:24 2016 From: kanzure at gmail.com (Bryan Bishop) Date: Thu, 25 Feb 2016 19:34:24 -0600 Subject: [Lightning-dev] [bitcoin-dev] SIGHASH_NOINPUT in Segregated Witness In-Reply-To: <20160226010746.GB10295@lightning.network> References: <20160226010746.GB10295@lightning.network> Message-ID: On Thu, Feb 25, 2016 at 7:07 PM, Joseph Poon wrote: > This would be achieved using a SIGHASH flag, termed SIGHASH_NOINPUT. It > does not include as part of the signature, the outpoint being spent > (txid and index), nor the amount. It however, would include the spent > outpoint's script as part of the signature. Note that this is just a Well if you are bothering to draft up a BIP about that SIGHASH flag, then perhaps also consider some other SIGHASH flag types as well while you are at it? Various proposed sighash types: http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010759.html "Build your own nHashType" proposal draft: https://github.com/scmorse/bitcoin-misc/blob/master/sighash_proposal.md jl2012's reply: http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010779.html petertodd's reply about OP_CODESEPARATOR linked back to this thread regarding "Build your own nHashType": http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-April/007771.html http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-April/007802.html http://gnusha.org/bitcoin-wizards/2014-12-09.log ((That particular thread had other replies which can be viewed here: http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-April/thread.html )) Also, there was a draft implementation of SIGHASH_NOINPUT: https://github.com/Roasbeef/bitcoin/commit/4b3c3f1baf7985208ceb6887261ee150ab6e3328 https://github.com/Roasbeef/btcd/commit/67830e506fa135d5239177340918cea39909e6a4 FWIW there was some concern about replay using SIGHAHS_NOINPUT or something: http://gnusha.org/bitcoin-wizards/2015-04-07.log - Bryan http://heybryan.org/ 1 512 203 0507