[bitcoin-dev] BIP 68 Questions

Rusty Russell rusty at rustcorp.com.au
Thu Jul 2 02:38:58 UTC 2015

Hi Mark,

        It looks like the code in BIP 68 compares the input's nSequence
against the transaction's nLockTime:

        if ((int64_t)tx.nLockTime < LOCKTIME_THRESHOLD)
            nMinHeight = std::max(nMinHeight, (int)tx.nLockTime);
            nMinTime = std::max(nMinTime, (int64_t)tx.nLockTime);
        if (nMinHeight >= nBlockHeight)
            return nMinHeight;
        if (nMinTime >= nBlockTime)
            return nMinTime;
So if transaction B spends the output of transaction A:

1.  If A is in the blockchain already, you don't need a relative
    locktime since you know A's time.
2.  If it isn't, you can't create B since you don't know what
    value to set nLockTime to.

How was this supposed to work?


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