Add rules--presently disabled--for using GetMedianTimePast as endpoint for lock-time calculations

The lock-time code currently uses CBlock::nTime as the cutoff point for time based locked transactions. This has the unfortunate outcome of creating a perverse incentive for miners to lie about the time of a block in order to collect more fees by including transactions that by wall clock determination have not yet matured. By using CBlockIndex::GetMedianTimePast from the prior block instead, the self-interested miner no longer gains from generating blocks with fraudulent timestamps. Users can compensate for this change by simply adding an hour (3600 seconds) to their time-based lock times.

If enforced, this would be a soft-fork change. This commit only adds the functionality on an unexecuted code path, without changing the behaviour of Bitcoin Core.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/policy/policy.h b/src/policy/policy.h
index 0ea0d435ad..cfe6a40526 100644
--- a/src/policy/policy.h
+++ b/src/policy/policy.h
@@ -43,6 +43,9 @@ static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY
 /** For convenience, standard but not mandatory verify flags. */
 static const unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS;
 
+/** Used as the flags parameter to CheckFinalTx() in non-consensus code */
+static const unsigned int STANDARD_LOCKTIME_VERIFY_FLAGS = 0;
+
 bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType);
     /**
      * Check for standard transaction types