From 2cccaf650fc3f8bfbd0c8429ee52245cb2db311f Mon Sep 17 00:00:00 2001 From: Luke Dashjr Date: Wed, 26 Jul 2023 19:45:51 +0000 Subject: bip-0300: Add OP_DRIVECHAIN --- bip-0300.mediawiki | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'bip-0300.mediawiki') diff --git a/bip-0300.mediawiki b/bip-0300.mediawiki index 6ee0760..20c5584 100644 --- a/bip-0300.mediawiki +++ b/bip-0300.mediawiki @@ -226,7 +226,7 @@ A sidechain fails to activate if: Otherwise, the sidechain activates (Active is set to TRUE). -In the block in which the sidechain activates, the coinbase MUST include at least one 0-valued OP_TRUE. This output becomes the initial CTIP for the sidechain. +In the block in which the sidechain activates, the coinbase MUST include at least one 0-valued OP_DRIVECHAIN output. This output becomes the initial CTIP for the sidechain. @@ -394,7 +394,7 @@ Every time a deposit/withdrawal is made, the old CTIP is spent and a new one is Every M5 is valid, as long as: -* It has at least one OP_TRUE output -- this becomes the new CTIP. +* It has at least one OP_DRIVECHAIN output -- this becomes the new CTIP. * The new CTIP has '''more''' coins in it, than before. @@ -405,7 +405,7 @@ We come, finally, to the critical matter: where users can take their money *out* M6 is invalid if: * The blinded hash of M6 does NOT match one of the approved Bundle-hashes. (In other words: M6 must first be approved by 13,150 upvotes.) -* The first output of M6 is NOT an OP_TRUE. (This OP_TRUE becomes the new CTIP. In other words: all non-withdrawn coins are paid back to the sidechain.) +* The first output of M6 is NOT an OP_DRIVECHAIN. (This OP_DRIVECHAIN becomes the new CTIP. In other words: all non-withdrawn coins are paid back to the sidechain.) * The second output is NOT an OP_RETURN script of exactly 10 bytes, of which 8 bytes are a serialized Bitcoin amount. * The txn fee of M6 is NOT exactly equal to the amount of the previous bullet point. @@ -413,8 +413,16 @@ Else, M6 is valid. (The point of the latter two bullet points, is to allow the bundle hash to cover the L1 transaction fee.) +===OP_DRIVECHAIN=== +This proposal adds a single new opcode, OP_DRIVECHAIN, which has strict semantics for usage. +OP_NOP5 (0xb4) is redefined as OP_DRIVECHAIN if and only if the entire script is OP_DRIVECHAIN followed by a single-byte push and OP_TRUE (exactly 4 bytes). +The single-byte push contains the sidechain number. +Note that this is not a "script number", and cannot be OP_1..OP_16 or any other kind of push; it is also unsigned, and must not be padded even if over sidechain number 127. +The final OP_TRUE is to ensure this change remains a softfork: +without it, sidechain numbers 0 and 128 would cause the legacy script interpreter to fail. +If an OP_DRIVECHAIN input is spent, the additional rules for M5 or M6 (see above) must be enforced. ==Backward compatibility== -- cgit v1.2.3