Author: jl2012 at xbt.hk 2015-09-17 07:43:02
Published on: 2015-09-17T07:43:02+00:00
Mark Friedenbach, a contributor to the Bitcoin community, proposed changing the rules regarding sequence numbers. He created two new repositories, one of which inverts the sequence number and interprets it as a fixed-point number, allowing up to five-year relative lock times using blocks as units or up to approximately two-year relative lock times using seconds as units. The other repository simply inverts the sequence number with nSequence=1 meaning one block relative lock-height and nSequence=LOCKTIME_THRESHOLD meaning one-second relative lock-height. Friedenbach discussed how many years of relative lock time are necessary, stating that it depends on why a relative lock time is needed and what it offers in addition to CHECKLOCKTIMEVERIFY. He only knows of one use case where confirmation takes so long that CLTV may expire before the transaction is confirmed. In this case, he believes that one year of relative lock time is more than enough since Bitcoin is essentially worthless if it takes months to confirm a transaction with a reasonable fee. Friedenbach also questioned whether there is any other use case for CSV that cannot be replaced by CLTV and found only one example in the BIP CSV draft.He then discussed the time-based relative lock time and noted that 256 seconds of granularity is sufficient since the block interval is 600 seconds. He believes that although it is not impossible to reduce the block interval in the future, it will require a hard fork, and they may just hard fork BIP68/CSV at the same time. Finally, Friedenbach talked about the bits required for time-based and block-based relative lock times and suggested that assuming a maximum of one year of relative lock times is appropriate. He further stated that he feels uncomfortable going less than a year for a hard maximum and could not think of a use case that would require more than a year of lock time.
Updated on: 2023-06-10T19:22:11.124021+00:00