Standard template for CHECKMULTISIG with 17~20 keys #13348

1. 
   jl2012 commented at 4:49 pm on May 30, 2018: contributor

   Making CHECKMULTISIG with 17~20 keys standard. Trying to redo #11545 after #13194 is merged
2. 
   sipa commented at 4:54 pm on May 30, 2018: member

   I think this should be conditional on the environment (and only enabled inside SegWit scripts).
3. 
   fivepiece commented at 5:02 pm on May 30, 2018: contributor

   Out of interest, does the soft fork nature (or rather, change of policy only) of it means that {17,18,19} checkmultisig(verify) will still count as 20 sigops (MAX_PUBKEYS_PER_MULTISIG) ? As in here : https://github.com/bitcoin/bitcoin/blob/fd96d54f39cf4f66890e0bb40812d47e69728cec/src/script/script.cpp#L161-L167
4. 
   jl2012 commented at 5:33 pm on May 30, 2018: contributor

   @sipa, I think legacy CHECKMULTISIG is always restricted to up to 3 keys, and P2SH is restricted by MAX_P2SH_SIGOPS
5. 
   sipa commented at 5:34 pm on May 30, 2018: member

   @jl2012 I’m aware, but I’m worried about situations were Solver is called on a script that isn’t found in a transaction that already passed validation.
6. 
   jl2012 commented at 5:35 pm on May 30, 2018: contributor

   oh…..actually, arbitrary scripts are already standard in witness v0….so this is only for wallet?
7. Standard template for CHECKMULTISIG with 17~20 keys 34d51f844b
8. Test: Standard template for CHECKMULTISIG with 17~20 keys 159e5aac91
9. jl2012 force-pushed on May 31, 2018
10. 
    instagibbs commented at 9:45 pm on June 4, 2018: member

    Yes they’re already standard. The only thing preventing their use was wallet code.
11. in src/script/standard.cpp:60 in 34d51f844b outdated

    56@@ -57,10 +57,18 @@ static bool MatchPayToPubkeyHash(const CScript& script, valtype& pubkeyhash)
    57     return false;
    58 }
    59 
    60-/** Test for "small positive integer" script opcodes - OP_1 through OP_16. */
    61-static constexpr bool IsSmallInteger(opcodetype opcode)
    62+/** Test for "small positive integer" script opcodes - OP_1 through OP_16, or a single byte push for 17 to 20. */
    

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    instagibbs commented at 9:49 pm on June 4, 2018:

    The old definition is used elsewhere still. Perhaps rename the function(or make a new one) to “IsCheckMultisigInteger” or something more direct?

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    jl2012 commented at 7:10 pm on June 5, 2018:

    I think it’s only used here, and is newly introduced in #13194

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    instagibbs commented at 7:13 pm on June 5, 2018:

    I meant the term “small integer” i.e. “encode small integer” etc
12. 
    jl2012 commented at 7:10 pm on June 5, 2018: contributor

    @fivepiece, no, this has nothing to do with sigop counting. They are still counted as 20
13. DrahtBot closed this on Jul 29, 2018

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14. 
    DrahtBot commented at 3:16 pm on July 29, 2018: member
15. DrahtBot reopened this on Jul 29, 2018

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16. 
    jl2012 commented at 12:30 pm on July 30, 2018: contributor

    Closed in favour of #13449
17. jl2012 closed this on Jul 30, 2018

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18. DrahtBot locked this on Sep 8, 2021

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jl2012 sipa fivepiece instagibbs DrahtBot