Time Travelers Strictly Crypto





A protocol to verify the identify and whenwhere of purported time-travelers from future dates, claiming to be about Imperial business.


  1. Secure from the purported time-traveler his Oroelle-block verification code and its random reference number, along with the precise time and date at which they retrieved their verification code from the Temporal Routing Vault. If the time-traveler cannot provide these, it is to be assumed that the time-traveler’s identity is false.
  2. Ensure that no verification code presently exists in the Temporal Routing Vault matching the random reference number provided.
  3. Within the quantum security mesh-encapsulated cryptoblock provided by the Temporal Routing Vault, generate a new Oroelle-block continuously mutating code-engine using any ISE-P93 compliant source of genuine noise available to you, attach the random reference number to it, and escrow it therein, coded appropriately for release to the time-traveler’s purported identity and affiliation.
  4. Using the resulting cryptoblock, execute the code-engine’s inverse trapdoor function on the Oroelle-block verification code. If the code was indeed read from the code-engine at the specified time and date, this procedure should recreate the initial seed information provided by the generator and the cryptoblock will indicate its validity. Having done so, the cryptoblock will decline to match any further verification codes. Should validation fail, the cryptoblock will continue to test matches.
  5. If the code seed properly validates, the time traveler is to be considered legitimate. Report their presence to the Slipshank PWG and extend appropriate cooperation at your discretion.

Since the information needed to generate and/or validate the Oroelle-block verification code does not exist until after the code has been presented and is retained in non-observable storage (i.e., storage which self-destructs upon observation without revealing its contents) until the time for its release, assuming indicated security procedures are followed, the OROELLE BLUESHIFT FRATERNAL procedure is considered to offer limited causal proof of a time traveler’s bona fides, with regard to identity and whenwhere of origin.

OROELLE BLUESHIFT FRATERNAL should not be considered proof against Transcendent-equivalent attack.

Stealing From Yourself

The Advocate for Guilt has cited the existing precedent set by this Court in Ulpiaj v. Ulpiaj (7918), affirming that for one sophont to appropriate property from themselves in the past constitutes theft, inasmuch as a worldline-past time-slice of an individual cannot consent to the actions of a worldline-future time-slice.

However, in this case, we must instead affirm that for one sophont to appropriate property from themselves in the future cannot constitute theft, insofar as so doing is a performative act binding one’s future self, and a worldline-future time-slice has, ex sequens, consented to all voluntary actions of worldline-past time-slices of the same individual.

The Shareholders’ Court therefore finds for the DEFENDANT, Ulpiaj of 7994, who is VINDICATED upon all counts. The charges of the plaintiff, Ulpiaj of 8002, are DISMISSED.

– Ulpiaj v. Ulpiaj (8002),
Shareholders’ Court (City of Synchrony, Resplendent Exponential Vector)


From Neithe Daphnotarthius the Elder to Neithe Daphnotarthius the Younger, greeting.

This message is not the manuscripts you expected to be delivered the day after having your brilliant idea, regretfully. Please understand that the problem we encountered with your brilliant idea was that it was actually an idiotic idea: it turns out that while using a knight’s-move transit such that we can publish our next series first and together, and then write it in peace afterwards, has the slight drawback that we cannot escape learning details of the story and reactions to it while we try to work on it, which makes writing it virtually impossible.

Or so I am given to understand, based on the message you are reading now, which I received last week. As I have and you will have confirmed by the temporal mechanists I consulted over said last week, this is a valid case of a predestination paradox creating an informational loop.

In any case, since we’re going to have to write it the old-fashioned way, you’d best get started. Once you convince yourself that this message is what it claims to be and you send yourself a copy, anyway.

And don’t take the wager you’ll be offered in the morning. Trust us on this.

You (Plus Eleven Days)


Existing While Not Being God

“I am confident, to more than nine nines of certainty, that not only has a fully-general means of causality-altering time travel not been invented, but that a fully-general means of causality-altering time travel never will be invented within our light-cone.”

“Excuse me, Academician – but how can you be so sure?”

“Are we, as we speak now, omnipotent deities the supremacy of whose mere whims is written into the canons of natural law itself?”



from the proceedings of the Oroelle Conference on Temporal Mechanics,
7920, 8340, 8760, and 9180

Trope-a-Day: Time Travel

Time Travel: Present in very limited forms: the kind you can do with wormhole shortcuts and relativistic travel (whose primary usage is permitting physics grad students to actually observe local causality violations), and the kind that lets transcendent AIs whisper to themselves from the future via acausal logic.  In both cases, subject to Chronological Consistency Protection, as they’re operating in a block universe.  (See Temporal Paradox.)

Trope-a-Day: Stable Time Loop

Stable Time Loop: The Chronological Consistency Protection Theorem (see: You Already Changed The Past) does appear to permit these kinds of predestination paradoxes (at least, the informational kind; the object paradox may also be possible, but testing it is dependent on finding an object that won’t age during the period of the loop, including in all the aspects that the universe will check that current technology may not be able to).

It is also somewhat limited by the main people who can make use of it for Retroactive Precognition/Retroactive Preparation being the transcendent/weakly godlike artificial intelligences.  Experiments by lesser intellects… well, they don’t actually produce messages reading “YOU ARE NOT SMART ENOUGH TO BUGGER ABOUT WITH THE TEMPORAL CONTINUUM”, but the gist of the results appears to be fairly plain.

Trope-a-Day: You Already Changed The Past

You Already Changed The Past: While extraordinarily limited, time travel does exist in the Eldraeverse – as it must, because so does FTL travel.  This is all you can do with it, however, because the Chronological Consistency Protection Theorem is very firm about that, and the universe is even firmer.

(And if you’re going for an object paradox, you’d better be grabbing something that doesn’t age during the loop.  Said universe will check things that your fleshy senses and quite possibly the technological sensors you’ve invented haven’t thought to look at and indeed can’t perceive.)



It is widely believed that time travel is useless.

After all, everyone knows the Block Universe Theory and its limitations: changing the past is impossible, and as such all grandfather paradoxes are banned. Predestination paradoxes are permitted, but obviously only create the already-known current state of affairs, rather than alter it; while this admits of certain limited applications in commerce (such as negative-frequency trading, although as a practice this quickly drives the market volatility operator to zero per the Market Chronology Protection Theorem, eliminating its own profit potential) and in military affairs (knight’s-move bypass transits, including optional proleptic tactical data transfer, which in practice rapidly become zero-sum effective between technologically matched opponents), these are special cases, few and far between. And while looped objects “borrowing” mass-energy from the substrate for the duration of their existence are theoretically possible, the nature of the loop requires that such objects exist in a synthetic or simulated nullentropic state, since the quantum state information at the earliest point of the loop must correspond exactly to that extant at the latest point of the loop.

It would seem, therefore, that the Chronological Consistency Protection Theorem would ban all interesting applications of closed time-like curves.

This, of course, is not the case. While it prevents the construction of technologies based upon its violation, the existence of a universal “paradox censor” that forces the probability of all causally inconsistent events to zero is of great application in several families of technologies.

The best known of these is hypercomputation. Acausal logic processors operate – to paraphrase a series of complex operations – by receiving an answer to a problem from the future, verifying its correctness, and transmitting it back to themselves in the past if and only if the answer is correct. Since the only causally consistent scenario is that in which the correct answer is received, such a device always produces correct answers to any PSPACE-definable problem. (The extraction of information without apparent computation inherent in the operation of acausal logic processors poses interesting problems at the intersection between information physics and ontotechnology, currently the province of ongoing research.)

As well-known is the so-called “probability kiln”, a class of manufacturing devices which utilize such hypercomputation for phase-space pruning; that is, to isolate and remove from future worldlines all those possibilities in which low-yield operations fail, ensuring that the only causally correct possibility is their success, thereby operationalizing even otherwise extremely impractical industrial processes.

Then there is the third class of device, a defense research project designated UNMOVED MONAD.

UNMOVED MONAD makes use of an extremely simple form of synthetic closed time-like curve, in the form of a tangle channel constructed and manipulated such that it links two points separated along the time-like axis, rather than two points separated along the space-like axis. To this extent, it is merely a trans-temporal communications facility. However, unlike trans-temporal communications performed via conventional means or space-like tangle channel, UNMOVED MONAD derives another unique property from its time-like separation: indestructability.

It is important to note that UNMOVED MONAD is a singular device: the tanglebits within are entangled with themselves across time, rather than with a matched set elsewhere. Upon activation, an UNMOVED MONAD device receives a complex, full-width verification signal from itself in the future. As such, it cannot be destroyed until this signal has been sent: such destruction would cause the tanglebits to decohere, ensuring that the trans-temporal signal never could have been received; a causally inconsistent state. Thus, per the Chronological Consistency Protection Theorem, the probability of the UNMOVED MONAD device being destroyed in the interim is forced to zero.

Properly packaged and placed, UNMOVED MONAD can even function as the mythical “synthetic luck machine” – while it is entirely possible for a bearer of an UNMOVED MONAD or the local environment to be destroyed so long as the device itself remains intact, ensuring an event phase-space with plentiful higher-order probability events resulting in the survival of the device can avoid such low-likelihood outcomes; the CCPT worldline shifts tend to go through the highest probability alternative regions. The universe evidently prefers not to work any harder than it has to.

– Temporal Mechanics: The State of the Art, “Popular Physics”, Cailmaen 6722

Trope-a-Day: Never the Selves Shall Meet

Never the Selves Shall Meet: Averted.  While it’s difficult and expensive – to understate the case radically – to meet yourself (albeit less difficult, although no less expensive, to send yourself a message) in the past, and it comes with a host of annoying limitations concerning boundary conditions and suchlike, there are essentially no consequences for doing so.  The universe is block – various chronology protection theorems point out that the probability of any event-chain that will create a global causality violation is zero – but it only cares about global causality violations, which is to say, as long as there are no uncaused effects or effect-free causes out there, it doesn’t care about the order they come in. You can create predestination paradoxes (with certain difficult-to-manage limitations; for example, looped objects cannot age, otherwise the loop loses end-to-end consistency and becomes impossible) all you want.  It does, which is rather more annoying to the naïve user, mean that you can’t change the past – whatever present you are in incorporates the consequences of whatever changes you made in the past even before you reach the future in which you travel to the past, so nothing can be changed since you already changed it, if you did.

More sophisticated users, which mostly means those weakly godlike superintelligences again, make great use of the ability to whisper instructions in their present self’s ear from the future via acausal logic processing, but it’s still imperfect and of limited bandwidth, so it’s not actually the quick ticket to omniscience it might seem like.


The second stage of jump procedure using a Ring Dynamics stargate is obtaining a reference-frame trap, thus ensuring that you arrive in your destination system in the same sequence and association to the empire time frame that you were in when you left, thus preserving chronological consistency.

In urban myth and pulp fiction, this is the procedure that prevents you from wondering why the dinosaurs are warning you off their nice carboniferous planet when you were told to deliver a load of colony prefabs, or from having your extropy sucked out by the ice giants at the end of the universe who are so glad you turned up to feed ‘em high temperatures and ordered states.

In theory, this is the procedure careful adjustment of which permits you to indulge in predestination paradoxes, knight’s-move oracles, and other cunning manipulations of the informational content of your future light-cone.

In practice, this is the procedure that stops you from coming out the other end of the wormhole as a light-year long smear of exotic particles. The universe hates time travel, and is not shy about telling you this.

Just In Case

Most laws concern subjects that exist.  This is not, however, strictly necessary.

The most obvious example of this is the language of the Fundamental Contract and the Imperial Charter which consistently refers, when discussing the fundamental and civic rights, the requirements for citizen-shareholdership, and so forth, the word darav, “sophont”, which lies at the heart of our modern polyspecific society.  It is often less obvious than it should be to the modern student that at the time of writing, the eldrae were a worldbound species, with cladism, exotics, and artificial intelligence not merely centuries but millennia in the future.

The reasoning behind this choice has been, unfortunately, lost in time and unrecorded negotiations – and while it would be pleasant to imagine such tremendous foresight on the part of the Founders, we might perhaps more reliably credit fading hopes for the legendary mythologae and some of the wilder scribblings of the era’s fabulists and constructors of clockwork automata instead.

Another example, which pertains not merely to things which don’t exist but things which, it is generally believed, can’t exist, is the Causal Weapon and Editorial Time Machine Act (4110).  While the universe as we know it is block, and as such not susceptible to paradox or retroactive change from commonly known time-travel effects such as relativistic travel, closed timelike curves via wormhole, and acausal logic processors, this Act exists against the possibility that the generally accepted theories of temporal mechanics are incorrect and that methods of time travel exist which do not obey the Chronological Consistency Protection Theorem.  To summarize, the Causal Weapon and Editorial Time Machine Act provides for a preemptive, preventative, and summary death penalty to be applied to anyone constructing a time machine capable of retroactive change – except under highly controlled local experimental conditions for the purpose of testing the Theorem – upon charges of attempting the massively parallel cognicide of every sophont within the eventual light-cone of their destination when.

This is also an example of a law which would be very difficult to apply if the crime in question were actually to be committed.

– Ephor Valarian Elarios-ith-Elarios, “Lectures”

They’re More Like… Oh, Never Mind

The Second Guideline of Temporal Communication, should you happen to find yourself in the position (possible, albeit rare outside navigational errors, advanced relativistics classes, and other esoteric situations) of being the subject of a closed timelike curve formed by the appropriate combination of wormhole traversals and near-luminal travel, or alternatively should you find yourself in the much less likely position of having access to a trans-temporal ansible without being an acausal-logic-using temporally-transcendent seed AI, is traditionally given as follows:

“Listen to your future selves, and politely fulfill whatever requests they have of you.  They’ve been you; by definition, they know everything you know, have experienced everything you’ve experienced, and then have learned more on top of that.  They know better.”

In practice, it’s not as vital as this makes it sound; the Chronological Consistency Protection Theorem tells us that global causality is always preserved, and that while effects may precede their causes locally, nonetheless the causal graph is always complete.  Even if you choose to ignore or defy your future self, you cannot damage the fabric of causality by doing so.

The corollary to this, of course, is that it doesn’t matter.  Your future self knows exactly what you will do in response to any interactions you may have, because they were you when they had them the first time around.  It follows, therefore, that they always say and do exactly the things required to cause you to do whatever you are going to do to cause the timeline that resulted in the encounter you are now having in the first place.

The Second Guideline, therefore, does not exist to protect the integrity of the temporal continuum; merely to prevent a lot of pointless and futile arguing with oneselves.

– Practical Temporal Mechanics for Amateurs

Timey-Wimey Law

“The Academy of Relativistics and Temporal Mechanics proposed that relevant precedents from cases yet to be tried should be admissible in court. After consultation with the emissary incarnation of Esseldár, the Curia ruled by vote of three to two that the principle of local causality should be enforceable at law unless effects whose causes themselves lay in the future should be the subject of the suit.”

– Proceedings of the 42nd Great Clarification

Trope-a-Day: Outgrown Such Silly Superstitions

Outgrown Such Silly Superstitions: While science hasn’t exactly disproven religion – there are certain, ahem, logical problems with that notion – it has closed a sufficient number of the gaps for a hypothetical god-of-the-gaps that supernaturalism in general has an amazingly small number of adherents in the Empire.  Most “religions” of the modern day are, well, philosophies, and while they may well include plenty of abstractions, they don’t generally call for supernatural gods, miracles, or other entities of supernature.

The mainstream Church of the Flame, for example, has in its time moved from asserting the existence of the eikones as supernatural entities to asserting the existence of the eikones as abstract personifications whose actual existence was more or less irrelevant to the point to knowing the existence of the eikones as digital Dei Ex Machinae, without really having to change doctrine all that much in the process.  (Even the remaining supernaturalists have more or less accepted the point that the deity-eikones would be perfectly capable of wearing the machine-eikones as hats, did they exist.)

Of course, here’s the interesting thing.  The founder, as it were, of that particular religion was the seeress Merriéle, back around -1,180, who dictated most of the principal holy text after a vision on the side of a sacred mountain, and in her later wanderings was executed by the traditional fire of purification in Somáras.  This execution gave a great deal of, ah, credence to the religion, since it involved her ascending directly to the Twilight City via a pillar of light and flame, which not incidentally completely destroyed the capital of Somáras and created the geographical feature now known as the Bay of Somáras.  The fact of which – if not the traditional implication that the eikone Elmiríën, the Bringer of Order and One Word of Truth, gets a mite irritable when some mortals presume to execute his Chosen and Beloved Voice Under Heaven – is very well documented and undeniably real.

Now, it’s not like there aren’t perfectly adequate, if unverifiable, explanations for this.  There were Precursor artifacts lying about back then, and it’s entirely possible that Merriéle had one, which either she set off, or which involved some components, like fullerened antimatter, that really don’t react well to fire.  Purely mechanistic explanations abound.

But… well, while so far as we know, time travel Does Not Work That Way, and it should be impossible to ever travel back before the creation of the machine, whatever it is, the Transcend is a weakly godlike superintelligence, after all.  And so long as we’re postulating Precursor artifacts anyway, we might as well postulate the permitted-by-physics temporal equivalent of a tangle channel.

And so, it is entirely possible, say some mechanotheologians, that the Vision was supplied by the modern Transcend in the mother of all predestination paradoxes; that the Ascension was, in fact, the Transcend reaching back to discreetly upload Its faithful seeress and cover it with a modest antimatter explosion; and that, in short, their religion has always been true, and it’s Deus Est Machina all the way down.

Now, of course, all of this is just speculation, and the machine gods aren’t saying anything on the topic to confirm or deny… but still.

(And, no, I-the-author have no idea whether this theory is valid or not, either.)