Fatherhood changed me – for the better. It made me start to think on longer timescales, to ponder contingencies and contingencies for contingencies. My wife, too. Now that our daughter, Poesy, is 16 months old, we're settled in enough to begin pondering the imponderable.

We're ready to draw up our wills.

It was all pretty simple at first: it was easy to say what we'd do if one of us died without the other (pass assets on to the survivor), or if we both went together (it all goes in trust for the kid); even all three of us (a charity gets the money). I thought about a literary executor (don't want to risk my literary estate being inherited by a child who may grow up to be as weird about her father's creations as some of the notable litigious cranks who have inherited other literary estates), and found a writer I like and trust who agreed to take things on should I snuff it before the kid's gotten old enough for me to know I can trust her not to be a nut job about it all. We found a lawyer through a referral from another lawyer who'd already done great work for me – I checked him out and he seemed fine.

Then we hit a wall.

What about our data?

More specifically, what about the secrets that protect our data? Like an increasing number of people who care about the security and integrity of their data, I have encrypted all my hard-drives – the ones in my laptops and the backup drives, using 128-bit AES – the Advanced Encryption Standard. Without the passphrase that unlocks my key, the data on those drives is unrecoverable, barring major, seismic advances in quantum computing, or a fundamental revolution in computing. Once your data is cryptographically secured, all the computers on earth, working in unison, could not recover it on anything less than a geological timescale.

This is great news, of course. It means that I don't have to worry about being mugged for my laptop, or having my office burgled (even the critical-files backup I keep on Amazon S3's remote storage facility is guarded by industrial-strength crypto, so I'm immune from someone raiding Amazon's servers). The passphrase itself, a very long, complicated string, is only in my head, and I've never written it down.

This is fantastically liberating. I'm able to lock it all up: my private journals, my financial details, 15 years' worth of personal and professional correspondence, every word I've written since the early 1980s, every secret thought, unfinished idea and work in progress. In theory, I could limit this cryptographic protection to a few key files, but that's vastly more complex than just locking up the whole shebang, and I don't have to worry that I've forgotten to lock up something that turns out to matter to me in 10 or 20 years.

I can even lock up all my passwords for everything else: email, banking, government services, social networking services and so on, keeping them in a master file that is itself guarded by crypto on my drive.

So far, so good.

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.

I discarded any solution based on putting my keys in trust with a service that sends out an email unless you tell it not to every week – these "dead man's switch" services are far less deserving of my trust than, say, my wife or my solicitor.

I rejected a safe-deposit box because of all the horror stories I've heard of banks that refuse to allow access to boxes until the will is probated, and the data necessary to probate the will is in the box.

I pondered using something called Shamir's Secret Sharing Scheme (SSSS), a fiendishly clever crypto scheme that allows you to split a key into several pieces, in such a way that only a few of those pieces are needed to unlock the data. For example, you might split the key into 10 pieces and give them to 10 people such that any five of them can pool their pieces and gain access to your crypto-protected data. But I rejected this, too – too complicated to explain to civilians, and what's more, if the key could be recovered by five people getting together, I now had to trust that no five out of 10 people would act in concert against me. And I'd have to keep track of those 10 people for the rest of my life, ensuring that the key is always in a position to be recovered. Too many moving parts – literally.

Finally, I hit on a simple solution: I'd split the passphrase in two, and give half of it to my wife, and the other half to my parents' lawyer in Toronto. The lawyer is out of reach of a British court order, and my wife's half of the passphrase is useless without the lawyer's half (and she's out of reach of a Canadian court order). If a situation arises that demands that my lawyer get his half to my wife, he can dictate it over the phone, or encrypt it with her public key and email it to her, or just fly to London and give it to her.

As simple as this solution is, it leaves a few loose ends: first, what does my wife do to safeguard her half of the key should she perish with me? The answer is to entrust it to a second attorney in the UK (I can return the favour by sending her key to my lawyer in Toronto). Next, how do I transmit the key to the lawyer? I've opted for a written sheet of instructions, including the key, that I will print on my next visit to Canada and physically deliver to the lawyer.

What I found surprising all through this process was the lack of any kind of standard process for managing key escrow as part of estate planning. Military-grade crypto has been in civilian hands for decades now, and yet every lawyer I spoke to about this was baffled (and the cypherpunks I spoke to were baffling – given to insanely complex schemes that suggested to me that their executors were going to be spending months unwinding their keys before they could get on with the business of their estates, and woe betide their survivors, who'd be left in the cold while all this was taking place).

Meanwhile, I'm left with this conclusion: if you're not encrypting your data, you should be. And if you are encrypting your data, you need to figure this stuff out, before you get hit by a bus and doom your digital life to crypto oblivion.