Timelock

A timelock is a rule in a bitcoin transaction or script under which funds can’t be spent before a set time or number of blocks has passed.

There are two main ways. The first sets a specific moment, a date or a block number: BIP-65 describes it (the OP_CHECKLOCKTIMEVERIFY instruction). The second sets a relative time from the moment a given deposit reached the network: BIP-112 describes it (OP_CHECKSEQUENCEVERIFY). Both let you build the condition “this spending path opens only after a year”.

In inheritance planning, a timelock is sometimes used for an extra access path: you can attach a rule to the same deposit so that after a long period of inactivity, named people can spend the funds. It’s an advanced solution. It needs well-chosen software, and you have to move the funds from time to time to reset the countdown.

A timelock doesn’t replace a will or instructions, and a wrong setup can lock funds for a long time. Use it only with someone who knows the subject, and after a test with a small amount.

Why it matters for your family

A timelock lets you pass on access without revealing keys while you’re alive, but your family must know that such a mechanism exists and when it kicks in. If you’re considering it, start with the pillar on crypto inheritance, and compare a plain key split with a 2-of-3 multisig wallet.