Implement excessive sighashing protection policy with loose sighash estimation #8756

1. 
   jl2012 commented at 5:20 am on September 19, 2016: contributor

   This is an alternative to #8755 and #8654

   This implements a static estimation of sighash size for a transaction. A transaction with more than 90bytes of sighash per weight is non-standard. This is equivalent to 36MB for an 100kB non-segwit transaction, or 360MB for a block in the worst case. All existing standard transactions with legitimate use of CHECK(MULTI)SIG should remain standard with this limit.

   The estimation of sighash is based on the assumption that SignatureHash is performed once only for each signature within a CHECKMULTISIG. This PR does not depend on any other policy or softforks like those in #8755. Despite the counting is more conservative, legitimate standard transactions for #8755 should also be standard in this implementation.

   Todo: unit tests

2. jl2012 force-pushed on Sep 19, 2016
3. jl2012 force-pushed on Sep 19, 2016
4. laanwj added the label P2P on Sep 21, 2016
5. 
   jl2012 commented at 6:04 pm on September 21, 2016: contributor

   A draft BIP is made for the detailed rationale of this PR: https://github.com/jl2012/bips/blob/sighash/bip-sighash.mediawiki
6. jl2012 force-pushed on Sep 30, 2016
7. jl2012 renamed this:
   Implement excessive sighashing protection policy with conservative counting
   Implement excessive sighashing protection policy with loose sighash estimation
   on Sep 30, 2016
8. 
   jl2012 commented at 10:36 am on September 30, 2016: contributor

   Unit tests are completed and related BIP updated
9. Add sighash limitation policy

   This implements a static estimation of sighash size for a transaction. A transaction with more than 90bytes of sighash per weight is non-standard. This is equivalent to 36MB for an 100kB non-segwit transaction, or 360MB for a block in the worst case. All transactions below 100kB with legitimate use of CHECK(MULTI)SIG should remain standard with this limit.

   200a37062a
10. Implement sighash cache for signature within CHECKMULTISIG

    This makes sure that SignatureHash is performed once only for each signature within a CHECKMULTISIG. Alternative to #8654.

    c1eea2ccce
11. jl2012 force-pushed on Oct 27, 2016
12. Test sighash limit policy e20b6c6b33
13. jl2012 force-pushed on Oct 28, 2016
14. 
    jl2012 commented at 3:18 am on December 23, 2016: contributor

    closed in favor of #8755
15. jl2012 closed this on Dec 23, 2016

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16. fanquake removed this from the "In progress" column in a project

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17. MarcoFalke locked this on Sep 8, 2021

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