[bitcoin-dev] BIP 113: Median time-past is a HARDfork, not a softfork!

Luke Dashjr luke at dashjr.org
Sun Nov 1 19:06:43 UTC 2015

BIP 113 makes things valid which currently are not (any transaction with a 
locktime between the median time past, and the block nTime). Therefore it is a 
hardfork. Yet the current BIP describes and deploys it as a softfork.

Furthermore, Bitcoin Core one week ago merged #6566 adding BIP 113 logic to 
the mempool and block creation. This will probably produce invalid blocks 
(which CNB's safety TestBlockValidity call should catch), and should be 
reverted until an appropriate solution is determined.

Rusty suggested something like adding N hours to the median time past for 
comparison, and to be a proper hardfork, this must be max()'d with the block 
nTime. On the other hand, if we will have a hardfork in the next year or so, 
it may be best to just hold off and deploy as part of that.

Further thoughts/input?


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