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| -rw-r--r-- | bip-noreplay.mediawiki | 61 |
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diff --git a/bip-noreplay.mediawiki b/bip-noreplay.mediawiki new file mode 100644 index 0000000..efd1a2c --- /dev/null +++ b/bip-noreplay.mediawiki @@ -0,0 +1,61 @@ +<pre> + BIP: ? + Layer: Consensus (soft fork) + Title: Generic anti-replay protection using Script + Author: Luke Dashjr <luke+bip@dashjr.org> + Comments-Summary: No comments yet. + Comments-URI: FIXME + Status: Draft + Type: Standards Track + Created: 2017-01-26 + License: BSD-2-Clause +</pre> + +==Abstract== + +This BIP describes a new opcode (OP_CHECKBLOCKATHEIGHT) for the Bitcoin scripting system that allows construction of transactions which are valid only on specific blockchains. + +==Copyright== + +This BIP is licensed under the BSD 2-clause license. + +==Specification== + +OP_CHECKBLOCKATHEIGHT redefines the existing NOP5 opcode. + +When executed, if any of the following conditions are true, the script interpreter will terminate with an error: + +* the stack has fewer than 2 elements; or +* the top item on the stack is not interpretable as a minimal-length CScriptNum; or +* the top item on the stack, when interpreted as a block height (see below) is not within the range of allowed blocks; or +* the second-to-top item on the stack, when interpreted as a block hash, has leading zeros; or +* the second-to-top item on the stack does not match the block hash of the block specified by the top item on the stack interpreted as a height. + +Otherwise, script execution will continue as if a NOP had been executed. + +FIXME: some way to mask out parts of the block hash for gambling/deterministic-random applications? + +===Block height interpretation and limits=== + +The specified block height may be either a negative number to specify a relative height, or a positive number for an absolute height. +A value of -1 refers to the block immediately preceding the block the transaction is mined it (but this is not a valid value, note). + +The specified height must not be more recent than the previous 100 blocks (that is, the largest negative value allowed is -101), nor older than 262144 blocks prior (ie, the smallest negative value is -262144). + +===Deployment=== + +This BIP will be deployed by "version bits" BIP9 with the '''name''' TBD and using '''bit''' TBD. + +For Bitcoin '''mainnet''', the BIP9 '''starttime''' will be TBD (Epoch timestamp TBD) and BIP9 '''timeout''' will be TBD (Epoch timestamp TBD). + +For Bitcoin '''mainnet''', the BIP9 '''starttime''' will be TBD (Epoch timestamp TBD) and BIP9 '''timeout''' will be TBD (Epoch timestamp TBD). + +==Motivation== + +In the event of a permanent blockchain split, some mechanism is desired by which the UTXOs valid in either chain may be spent without the transaction being validly replayable on the other chain. + +Additionally, there are some cases in normal Bitcoin operation wherein a wallet may need to respend a payment, but must guarantee its respend cannot be mined in the same block as a previous payment which has been recently conflicted by a double-spend. + +==Reference Implementation== + +TODO |