At the end of Mastering Bitcoin Chapter 7, in the "Complex Script Example", they ask this question in regards to the script:

How do the partners "reset" the clock every 29 or 89 days to prevent the lawyer from accessing the funds?

Does anyone have a good explanation for this? I feel like I missed something in the timelock section that might have explained this, but I'm not seeing it.

2 Answers 2


If at least two of the partners are cooperative with each other, they can move the funds at any time, even before the 30 days have elapsed. They can spend the output at any time using the second redeem path, with at least two signatures, for example:

0 <Mohammed's Sig> <Zaira's Sig> TRUE TRUE

So to 'renew' the time, they just need to spend the output by creating a new transaction with exactly the same output script, every time they want to renew it. Because the times use CSV, they are relative timelocks not absolute, so they don't need to be modified for each new transaction. Once a new transaction has been created which spends the output of the old one, that old output cannot be spent a second time so the lawyer must wait for the 30/90 days to elapse on the new transaction, and so on.


They 'reset' the clock by moving the funds to a new output before the period ends.

  • Can you elaborate a bit more? Commented Nov 26, 2017 at 18:53

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