From d30f1c6d0b02f1c22086852e274b3c4ba98d2434 Mon Sep 17 00:00:00 2001 From: BtcDrak Date: Tue, 24 Nov 2015 13:08:54 +0000 Subject: More clearly define script execution failure pathway --- bip-0112.mediawiki | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) (limited to 'bip-0112.mediawiki') diff --git a/bip-0112.mediawiki b/bip-0112.mediawiki index 8821bf5..db5147d 100644 --- a/bip-0112.mediawiki +++ b/bip-0112.mediawiki @@ -20,16 +20,16 @@ being spent. ==Summary== CHECKSEQUENCEVERIFY redefines the existing NOP3 opcode. -When executed, the script interpreter continues as if a NOP was executed -so long as: +When executed, if any of the following conditions are true, the script interpreter will terminate with an error: -* the top item on the stack is greater than or equal to 0; and -* the top item on the stack does not have disable flag (1 << 31) set; and -* the transaction version is 2 or above; and -* the transaction input's sequence number does not have the disable flag (1 << 31) set; and -* the top item on the stack and the transaction input's sequence number are both relative lock-times of the same type, and sequence number is greater than or equal to the top item on the stack. +* the top item on the stack is less than 0; or +* the top item on the stack has the disable flag (1 << 31) unset; and +** the transaction version is less than 2; or +** the transaction input sequence number disable flag (1 << 31) is set; and +** the relative lock-time type is not the same; or +** the top stack item is greater than the transaction sequence (when masked according to the BIP68); -Otherwise, script execution terminates with an error. +Otherwise, script execution will continue as if a NOP had been executed. BIP 68 prevents a non-final transaction from being selected for inclusion in a block until the corresponding input has reached the specified age, as measured in block-height or block-time. By comparing the argument to CHECKSEQUENCEVERIFY against the nSequence field, we indirectly verify a desired minimum age of the the output being spent; until that relative age has been reached any script execution pathway including the CHECKSEQUENCEVERIFY will fail to validate, causing the transaction not to be selected for inclusion in a block. @@ -196,9 +196,9 @@ and correspondingly in Bob's commitment transaction: ELSE EQUAL IF + "24h" CHECKSEQUENCEVERIFY DROP DUP HASH160 CHECKSIGVERIFY ELSE - "24h" CHECKSEQUENCEVERIFY DROP "2015/10/20 10:33" CHECKLOCKTIMEVERIFY DROP DUP HASH160 CHECKSIGVERIFY ENDIF @@ -298,13 +298,13 @@ semantics and detailed rationale for those semantics. return false; // Sequence numbers with their most significant bit set are not - // consensus constrained. Testing that the transaction's sequence + // defined by BIP68. Testing that the transaction's sequence // number do not have this bit set prevents using this property // to get around a CHECKSEQUENCEVERIFY check. if (txToSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) return false; - // Mask off any bits that do not have consensus-enforced meaning + // Mask off any bits that do not have BIP68 consensus-enforced meaning // before doing the integer comparisons of ::VerifySequence. const uint32_t nLockTimeMask = CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG | CTxIn::SEQUENCE_LOCKTIME_MASK; @@ -365,7 +365,7 @@ related proposals for improving Bitcoin's lock-time capabilities, including: OP_CHECKLOCKTIMEVERIFY, [https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki BIP 68]: -Consensus-enforced transaction replacement signalled via sequence numbers, +Relative lock-time through consensus-enforced sequence numbers, and [https://github.com/bitcoin/bips/blob/master/bip-0113.mediawiki BIP 113]: Median-Past-Time-Lock. @@ -386,7 +386,7 @@ Thanks to Eric Lombrozo and Anthony Towns for contributing example use cases. ==References== -[https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki BIP 68] Consensus-enforced transaction replacement signalled via sequence numbers +[https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki BIP 68] Relative lock-time through consensus-enforced sequence numbers [https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki BIP 65] OP_CHECKLOCKTIMEVERIFY -- cgit v1.2.3