As far as I could research the first such solution was proposed at this bitcoin talk thread: https://bitcointalk.org/index.php?topic=4479452.0 but may be there are earlier ideas.
In real world we assume today that after a person is no longer alive the assets will be passed to some other party, depending on the inheritance law of a particular country. In crypto world we assume something radically different. One who owns the private keys are in possession of assets.
Of course proponents of the real world “reality” will say, that a country law is still a country law and it applies in every asset. But as we all know from jurisprudence there is a de jure and de facto laws. If you can not enforce the law de jure, it becomes a law de facto. How can we enforce that a dead person submit their private key to the law enforcement body?
No ultimate decentralized solution exist today. All practical solutions are based on some form of custody. Custody, like a law, is practically very hard and centralised. We need decentralized solution to make sure we pass our wealth according to our will, without relaying on centralised custody, good faith of other people holding multisignature keys, good standing of other people not loosing these keys, and generally other off chain mechanisms such as oracles to attest we are in fact no longer alive.
Imagine a Wallet smart contract where all person’s tokens are stored, signed by their private key. Now let’s imagine a Will smart contract where all inheritance destination addresses are stored according to the Will distribution. Let’s write an exwill function in a Wallet smart contract that will send all tokens to the Will smart contract after say one year if the Wallet smart contract did not make a single transaction signed by owner private key. Anyone can call the exwill function at any time of course.
There is no limit to rules under the exwill function. Wallet contract could for example ‘leak” funds per period to accommodate for some trust mechanisms and so on.
