From fbc5f37d0b78e83e37678178b4b5bea1b1cd8028 Mon Sep 17 00:00:00 2001 From: Tadge Dryja Date: Mon, 21 Dec 2015 22:36:28 -0500 Subject: [PATCH 1/2] remove dependencies on mathematics --- revocation/shachain.go | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/revocation/shachain.go b/revocation/shachain.go index 52d724ad3..d262a3559 100644 --- a/revocation/shachain.go +++ b/revocation/shachain.go @@ -72,6 +72,12 @@ func derive(from, to uint64, startingHash [32]byte) [32]byte { numBranches := from ^ to toDerive := uint64(math.Log2(float64(numBranches))) // uh..... + // math? floats? nahhh! :) bit-flipp-y way to do it: + for toDerive = 0; numBranches>>toDerive > 0; toDerive++ { + } + // ^^^this rounds up instead of down, may be off by 1? + toDerive-- // needed? + for i := int(toDerive - 1); i >= 0; i-- { if (numBranches>>uint(i))&1 == 1 { // Flip the ith bit, then hash the current state to From 55c8710cb98d12e21f42eb57a1d1f35bec3fdc7f Mon Sep 17 00:00:00 2001 From: Joseph Poon Date: Tue, 22 Dec 2015 16:45:21 -0800 Subject: [PATCH 2/2] Minor optimization in script opcodes --- lnwallet/channel.go | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/lnwallet/channel.go b/lnwallet/channel.go index d5775f192..6e79723a4 100644 --- a/lnwallet/channel.go +++ b/lnwallet/channel.go @@ -254,12 +254,12 @@ func createCommitTx(fundingOutput *wire.TxIn, ourKey, theirKey *btcec.PublicKey, //simple and assume dual funder (with both funding above reserve) func createCLTVFundingTx(fundingTimeLock int64, ourKey *btcec.PublicKey, theirKey *btcec.PublicKey) (*wire.MsgTx, error) { script := txscript.NewScriptBuilder() - //See how many entries there are - //2: it's a 2-of-2 multisig - //anything else: assume it's a CLTV-timeout 1-sig only - script.AddOp(txscript.OP_DEPTH) - script.AddInt64(2) - script.AddOp(txscript.OP_EQUAL) + //In the scriptSig on the top of the stack, there will be either a 0 or + //1 pushed. + //So the scriptSig will be either: + // <1> + // <0> + //(Alice and Bob can be swapped depending on who's funding) //If this is a 2-of-2 multisig, read the first sig script.AddOp(txscript.OP_IF)