The Quantum Thief

‘It was … sudden.’ I look down at the Watch. The sunlight glints off it, and again, I notice the engravings on the side. ‘It felt … private.’

She grabs my face with impossibly strong fingers and turns it up. Her eyes look unblinking into mine, angry and green.

‘As long as we are in this together, there is no private. Do you understand? If I need to know, you will tell me your every childhood memory, every masturbation fantasy, every teenage embarrassment. Is that clear?’

‘I do wonder,’ I say slowly and carefully, ‘if there is something affecting your professionalism. And I would note that I’m not the one who screwed up the Prison exit. I’m just the one who got us out of it.’

She lets go and looks out of the window for a moment. I get up and get a drink from the fabber, Kingdom-era cognac, without offering her a glass. Then I study the Watch again. There are zodiac symbols, in a grid of seven by seven, Mars, Venus, and others I don’t recognise. And underneath, cursive script: To Paul, with love, from Raymonde. And that word again, Thibermesnil, in copperplate typeface.

Could you have a look at these? I whisper to Perhonen. You will still talk to me without hitting me, right?

I don’t need to hit you, the ship says. I have lasers. I’ll see what I can find. Its tone is unusually terse: I’m not surprised. I tell myself it’s the cognac alone that makes my face burn.

‘All right,’ Mieli says. ‘Let’s talk about this thing you stole.’

‘Found.’

‘Whatever.’ She holds it up. ‘Tell me about this. The Oubliette data I have is clearly obsolete.’ Her tone is colourless. A part of me wants to break that icy veneer again, dangerous or not, to see how deep it goes.

‘It’s a Watch. A device that stores Time as quantum cash – unforgeable, uncopyable quantum states that have finite lifetimes, counterfeit-proof, measures the time an Oubliette citizen is allowed in a baseline human body. Also responsible for their encrypted channel to the exomemory. A very personal device.’

‘And you think it was yours? Does it have what we need?’ ‘Maybe. But we are missing something. The Watch is meaningless on its own, without the public keys – gevulot – inside the brain.’

She taps the Watch with a fingernail. ‘I see.’

‘This is how it works. The exomemory stores data – all data – that the Oubliette gathers, the environment, senses, thoughts, everything. The gevulot keeps track of who can access what, in real time. It’s not just one public/private key pair, it’s a crazy nested hierarchy, a tree of nodes where each branch can only by unlocked by the root node. You meet someone and agree what you can share, what they can know about you, what you can remember afterwards.’

‘Sounds complicated.’

‘It is. The Martians have a dedicated organ for it.’ I tap my head. ‘A privacy sense. They feel what they are sharing, what is private and what isn’t. They also do something called co-remembering, sharing memories with others just by sharing the appropriate key with them. We just have the baby version. They give the visitors a bit of exomemory and an interface to it, reasonably well-defined. But there is no way we can appreciate the subtleties.’

‘And why would they do this?’

I shrug. ‘Historical reasons, mainly: although not much is known about what exactly happened here after the Collapse. The commonly accepted version is that someone brought a billion gogols here for a private terraforming project and set themselves up as a King. Until the gogols rebelled. Anyway, the fact that the gevulot system is in place is pretty much why Sobornost has not just eaten this palace yet. It would be too much trouble to decrypt everything.’

All right, you two, says Perhonen. Sorry about the delay, I didn’t want to interrupt. The symbols are astrological. The exact sequence only appears in one source, Giulio Camillo’s Memory Theatre. It’s an occult system from the Renaissance. Thibermesnil is a castle in France. Here are the details. She sends a spime down our neutrino channel. Mieli looks at it and leaves it hanging in the air, between us.

‘Fine,’ she says. ‘So, what does all that mean?’

I frown. ‘I have no idea. But I think everything we need is in my old exomemory. What we need to do is to figure out how to get to it. I think I need to become Paul Sernine again, whoever he was.’ I pour myself some more cognac.

‘And where do you think your old body is? Did he – you – take it with you when he left? And what is the point of those markings?’