Where to get the password of a deceased loved one?

Cory Doctorow investigates in the Guardian the really hard question. It is wise to protect your digital data with encryption. But what happens if you pass away? How will your loved ones be able to access the encrypted data?

But what if I were killed or incapacitated before I managed to hand the passphrase over to an executor or solicitor who could use them to unlock all this stuff that will be critical to winding down my affairs - or keeping them going, in the event that I'm incapacitated? I don't want to simply hand the passphrase over to my wife, or my lawyer. Partly that's because the secrecy of a passphrase known only to one person and never written down is vastly superior to the secrecy of a passphrase that has been written down and stored in more than one place. Further, many countries's laws make it difficult or impossible for a court to order you to turn over your keys; once the passphrase is known by a third party, its security from legal attack is greatly undermined, as the law generally protects your knowledge of someone else's keys to a lesser extent than it protects your own.