That's it. Now he only needs to create a "switch" to spend his coins to the address A whenever he dies. A button on his phone when he's on his deathbed, or something.
That's not a dead man's switch though, that's just a... switch
The whole idea behind a dead man's switch is that it's triggered by the inactivity of the dead-man-to-be rather than by a last second attempt to send off a signal (the latter which could faile due to the dead-man-to-be's untimely demise).
Make a timelocked transaction that spends his coins when he's a 100 years old, or a 120, some time that he obviously won't reach.
Broadcast it and that's it.. If he decides to spend his coins before that, then do it, otherwise, they'll be transferred to his friend.
Broadcast it and that's it.. If he decides to spend his coins before that, then do it, otherwise, they'll be transferred to his friend.
Prematurely broadcasted timelocked transactions are invalid and ignored by the network. That's why additional application logic is needed to broadcast the timelocked transaction after the timelock has passed.
But as a quick answer to you bob123 :
1. HeRetiK's solution also stores the timelocked transaction on a server.
2. You can easily change my solution from "press a button to send the tx", to "press a button occasionally before to prevent the tx from being sent from the server."
My solution also doesn't expose his private keys, or endanger his money, all of those are only known to him. The server holds 2 transactions to addresses he already owns.
1. HeRetiK's solution also stores the timelocked transaction on a server.
2. You can easily change my solution from "press a button to send the tx", to "press a button occasionally before to prevent the tx from being sent from the server."
My solution also doesn't expose his private keys, or endanger his money, all of those are only known to him. The server holds 2 transactions to addresses he already owns.
The timelocked transaction does absolutely nothing until after the timelock has passed however, that's the beauty of it
If the server gets compromised or the software fails for some other reason, a regular transaction would cause the coins to move prematurely. With a timelocked transaction you have the added security of the Bitcoin blockchain.