From 4d79098ad548874ca6e4c09d873fc2f481e6edb4 Mon Sep 17 00:00:00 2001 From: Peter Todd Date: Mon, 10 Mar 2014 16:38:44 -0400 Subject: [PATCH] Increase IsStandard() scriptSig length Removes the limits on number of pubkeys for P2SH CHECKMULTISIG outputs. Previously with the 500 byte scriptSig limit there were odd restrictions where even a 1-of-12 P2SH could be spent in a standard transaction(1), yet multisig scriptPubKey's requiring more signatures quickly ran out of scriptSig space. From a "stuff-data-in-the-blockchain" point of view not much has changed as with the prior commit now only allowing the dummy value to be null the newly allowed scriptSig space can only be used for signatures. In any case, just using more outputs is trivial and doesn't cost much. 1) See 779b519480d8c5346de6e635119c7ee772e97ec872240c45e558f582a37b4b73 Mined by BTC Guild. --- src/main.cpp | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/src/main.cpp b/src/main.cpp index e8fb26de888..8ed811c1a91 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -515,10 +515,14 @@ bool IsStandardTx(const CTransaction& tx, string& reason) BOOST_FOREACH(const CTxIn& txin, tx.vin) { - // Biggest 'standard' txin is a 3-signature 3-of-3 CHECKMULTISIG - // pay-to-script-hash, which is 3 ~80-byte signatures, 3 - // ~65-byte public keys, plus a few script ops. - if (txin.scriptSig.size() > 500) { + // Biggest 'standard' txin is a 15-of-15 P2SH multisig with compressed + // keys. (remember the 520 byte limit on redeemScript size) That works + // out to a (15*(33+1))+3=513 byte redeemScript, 513+1+15*(73+1)=1624 + // bytes of scriptSig, which we round off to 1650 bytes for some minor + // future-proofing. That's also enough to spend a 20-of-20 + // CHECKMULTISIG scriptPubKey, though such a scriptPubKey is not + // considered standard) + if (txin.scriptSig.size() > 1650) { reason = "scriptsig-size"; return false; }