Photo IDs (for instance, a driver's licence or passport) are essential in many aspects of life (driving, buying alcoholic beverages, crossing international borders, voting in many places, etc.). As the name indicates, however, they rely on being able to guarantee that the person holding the ID does, in fact, look reasonably like the photo on the ID, which would pose obvious problems when dealing with someone who can (voluntarily or not) change their appearance.

One partial solution could be to require that the shapeshifter assume a specific standard form for tasks like voting or going through security, and to use that standard form for the ID picture, but that wouldn't work for things like driving (what if a traffic cop pulls them over for a broken taillight and asks for their licence and registration when they happen to be in a form different from their standard form?), or with shapeshifters who have incomplete or no control over their shapeshifting.

How to solve the seeming incompatibility of shapeshifters and photo IDs?

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    $\begingroup$ could you expand on what you mean by photo ID ( photo of face like currently, or photo of anything, or even image of anything?), and what your shapeshifters are capable of, exactly (mass change?, skeleton?, only forms they saw?, only shape or also texture, internal makeup(e.g. blood vessels,...)?) $\endgroup$
    – bukwyrm
    Commented Apr 8, 2019 at 4:59
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    $\begingroup$ Have you ever met anyone who is actually recognizable from a driver's license photo? $\endgroup$
    – jamesqf
    Commented Apr 8, 2019 at 16:12
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    $\begingroup$ Is this a society where everyone can shape shift, or is that a special ability only a few have? Can they mimic other people? If yes, how perfect of a copy is it? $\endgroup$
    – Kat
    Commented Apr 8, 2019 at 18:39
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    $\begingroup$ Definitely related, possible duplicate: How to verify or establish identity where shapeshifters exist $\endgroup$
    – user
    Commented Apr 8, 2019 at 20:33
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    $\begingroup$ @aCVn: Not a duplicate - that question asks about distinguishing shapeshifters from non-shapeshifters in a medieval setting, while mine asks about identifying individual shapeshifters in a modern setting. $\endgroup$
    – Vikki
    Commented Apr 9, 2019 at 2:52

11 Answers 11


Here's the thing; any form of identification, whether it be a letter of passage from the King, a passport, a photo ID, a biometric signature, a PIN - they all require a singular ubiquitous element in order to work.


Before Photo IDs, we still had drivers licenses, but they were paper and contained a name, an address, and a physical description of the driver (male, Caucasian, 170cm, black hair, brown eyes, etc.) and these were taken as proof of identification. We switched to photo IDs because they were supposed to be harder to cheat, and they are. But, they're not impossible to cheat which is another problem.

Biometrics are similar - biometrics are really useful the second time you ever meet someone, and their sole strength is ensuring that a person isn't registered in a system multiple times. Yes, they're also a part of authentication, but even the best biometrics have Detection Error Tradeoff (DET) curves associated with them - occasionally, they get it wrong and let someone in they shouldn't or lock someone out they shouldn't.

The point being, that authentication of identity relies on one or more of three elements,

What you have (Photo ID key or swipe card)
What you know (password)
What you are (biometrics)

in some combination that can be trusted to a point where the risk is acceptable.

This is in fact the key point - all authentication protocols are in effect risk mitigation systems, not risk avoidance systems. You will NEVER eliminate the risk of either false positives or false negatives in your authentication process unless you set up a system where the authentication process represents a practical prohibition on access to whatever system you have.

In other words, your cop pulling over someone for a broken taillight is really just doing a cursory check that the person in front of him isn't a wanted killer (which is highly unlikely) because no real damage has been done and he just wants to issue the infringement notice to the right person.

So - your shapeshifters may not have a photo ID at all - it kinds of defeats the purpose. What they may have is some form of DNA test or some other simple to use identifier that is much harder for a shapeshifter to circumvent.

In point of fact, if shapeshifters are a part of your society, normal biometrics like photo IDs, facial recognition, fingerprints, etc. are now all redundant for everyone. Why? Because you don't want your shapeshifter impersonating a normal person when the police pulls him over for a broken taillight and it turns out he's just killed the original owner of the car.

Ultimately I don't know what kind of identity authentication you would employ in a society with shapeshifters (and it's probably a really good question to ask here in its own right) but the simplest answer to your question about how to resolve the incompatibility between photo IDs and shapeshifters is not to use photo IDs.

The very existence of your shapeshifters has brought the trust value of photo IDs down to zero.

Assuming that your shapeshifters have a static DNA profile, what you'd probably find is that pretty quickly you'd see the advent of portable DNA sniffers being used for identification purposes by police, airports, etc. Most 'what you have' models of authentication would be abandoned pretty quickly and replaced with some other mechanism that can be trusted to the same level as photo IDs were pre-shapeshifters.

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    $\begingroup$ Depending on the level of control the shapeshifter has, fingerprints might still be viable. If they have them in the first place. They can look at your face and copy it. Or even sample your DNA. But even identical twins have different fingerprints, so unless the shapeshifter studies and deliberately replicates the prints (or has some sort of supernatural information bypass to get them), they still would not be a match. $\endgroup$ Commented Apr 8, 2019 at 3:55
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    $\begingroup$ @Xavon_Wrentaile if fingerprints are still valid, then iris scans are likely to be even better for similar reasons. Of all the biometric tests you can perform iris scanning has the lowest DET curve and covers off things like identical twins because it's effectively measuring tears in the iris as a result of growth. I can't imagine a scenario where a shapeshifter has set fingerprints but can change an iris. But either way, it's a good catch. $\endgroup$
    – Tim B II
    Commented Apr 8, 2019 at 5:10
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    $\begingroup$ @TimBII but the Shapeshifter didn't grow into their body, maybe they don't have iris tears or fingerprints at all? $\endgroup$ Commented Apr 8, 2019 at 11:07
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    $\begingroup$ "What you have", in the something you have/know/are triad, is just the physical artefact. A photograph can be considered biometrics. $\endgroup$
    – user
    Commented Apr 8, 2019 at 20:34
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    $\begingroup$ This is a really good answer. However, "What you have (Photo ID)" needlessly mixes in biometrics for an element that doesn't need it. Consider an edit: "What you have (ID)". $\endgroup$ Commented Apr 9, 2019 at 11:00

Whilst photographic identification may not work, as Tim B II pointed out, i offer a different method of identification, microchips.

Much in the same way we put microchips in cats and dogs so, if they got lost, we can identify their owner and return them, you could have microchips in shape shifters. These chips would identify who the shifter really is, their address, criminal record, driving qualifications, insurance etc.

To use your scenario, if a shifer was pulled over by the police and asked for id, either they would present no id and be arrested or they would tell the officer they have microchip id. At which point, the officer would scan the chip and their records would be able to accurately identify who the chipped person is.

To use a different scenario, airports require you to have a passport. However, some passports have microchips in them which identifies the owner and allows for faster processing. Much in the same way, a shape shiffer could be scanned as though they were a chipped passport. You may even have metal detectors which can identify chips and brings up the records of the shifter as they are being scanned.

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    $\begingroup$ How many millions of people are likely to be screaming over this blatant violation of rights and freedoms, exactly? I know I would be one of them, and I'm pretty sure that in at least some countries, this would be legally and/or constitutionally prohibited. You're talking about implanting locator chips into people (I know, you don't mention any GPS, but that is what people will justifiably conclude, no matter what the government claims), and this would also run afoul of discrimination laws if you do not try to apply it to all civilians and insist on having special rules for shapeshifters. $\endgroup$
    – Palarran
    Commented Apr 8, 2019 at 10:26
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    $\begingroup$ @Palarran: WE would perceive it as a violation of rights/freedoms if you were to introduce it now; however, introduce sooner in history and it likely would seem palatable to the majority. Different world, different ethics. Even more interesting, introduce before GPS exists and people may be used to it by the time GPS comes around and not worry about location issue. (As for the location issue itself, with so many people willingly carrying mobile phones around... meh) $\endgroup$ Commented Apr 8, 2019 at 12:27
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    $\begingroup$ @Palarran Some could also say that being forced to be photographed than carry the photo with you (with a RFID chip, no less) is a violation of rights. $\endgroup$ Commented Apr 8, 2019 at 13:01
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    $\begingroup$ @Palarran why wouldn't shapeshifters have special rules? Anti-discrimination laws exist to overcome social and cultural biases, wherease shapeshifters are clearly dramatically different from any normal human and their very existence seriously undermines trust. Given today's political climate, those millions are just as likely to be screaming for the extermination of these duplicitous aliens, coming over here and stealing our identities, right? $\endgroup$ Commented Apr 8, 2019 at 14:27
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    $\begingroup$ @Palarran: (1) Microchip IDs are not powered devices either. I believe they're essentially the same as the passive RFID chips often found in transit passes, although I'd welcome corrections. (2) Nothing in the question suggests to me that IDs for shapeshifters would be any more mandatory than, say, Canadian or US passports or driver's licenses. Did I miss something? (3) I'm trying to understand why, given the similarities I just outlined between this answer's microchip IDs and the forms of ID that are already common in our world, you believe the microchip IDs would be received so differently. $\endgroup$
    – Vectornaut
    Commented Apr 9, 2019 at 2:57

Smile and say x-Ray

Just because they can change their physical form does not mean that a picture in a non-visible light would not show some identifying features.
For ease we can call this their "Aura" and for sake of argument it is like a fingerprint for each entity.


Sir please stop smiling and change into a ball.

When a shapeshifter changes they release a [thing] (neutrino, beta particle, photon, ...) or uncontrollably their "skin" cycle through a unique colour pattern. As long as the correct camera is pointed at them while they're changing, they can be identified. The key identifying markers can be put on a card and compared with what is taken from the camera.


An alternative idea I thought of, what if shape shifters do have a standard form BUT it is not shown on their ID.

What I mean is, much in the same way you send off pictures for a passport photo or driver’s license, shape shifters would send off pictures of their standard form. However, unlike passport photos, their photograph would not be printed on their ID. Instead, the photo would simply be kept in their records, along with the rest of the information you’d expect on a passport

On their ID it has all the information you’d expect (passport number, date of birth, expiry date etc) but no photograph and the word Shapeshifter in big bold letters at the top. When a shapeshifter needs to be identified, the officer would ask them “please assume your standard form”. If the form matched the picture in the records, that is proof of identification as only the owner would know what their standard form is. If another shapeshifter tried to use their ID, they would fail the “standard form” question as they do not know what it is, only the ID’s owner does and, as the picture is not printed on the ID, they have no way of guessing what it is either.

Note that I use the term ‘standard form’. This instead could be replaced with a ‘security form’, a form that they would not use in everyday life, its only purpose is for passing security questions. Also, this method would not work for involuntary shifters, they would likely require a different ID method, such as microchipping as I mentioned previously.

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    $\begingroup$ Note that this "standard form" is like a password or PIN, and can be easily shared or stolen throughout a community of shapeshifter. Of course, you don't want to share your identity (standard form) because you don't want anyone to impersonate you, but I can easily see a crime where two or more shapeshifters assume the standard form of each others when questioned to make alibis for each others. $\endgroup$
    – Vylix
    Commented Apr 8, 2019 at 9:49
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    $\begingroup$ @Vylix, I like this security flaw, because it mirrors one we see in our world, whenever signatures and national identification numbers are used for identity verification. The "standard form" reminds me very much of a signature! The "security form" could be made less leaky by confining some important details to a body part, like a palm, that could easily be scanned while remaining hidden from passers-by. $\endgroup$
    – Vectornaut
    Commented Apr 8, 2019 at 22:39

Many licenses have endorsements and restrictions that are printed on a license for a driver. Endorsements are exclusively for commercial drivers licenses and permit the driver to drive vehicles with additional restrictions. For example, P is used to endorse a driver to drive a comercial vehicle that carries 16 or more passengers (Busses), H permits the driver to drive Hazardous Materials, T permits the driver to drive Tanker trucks, and X permits the Driver to Drive Hazardous Materials in Tanker Trucks (i.e. Gasoline). These are mandated by the Federal Government and are universal.

Restrictions mean that the liscense is only good if the driver is driving under certain conditions, which, if violated, will be treated as reckless endangerment. If you do not have glasses, find a buddy that has glasses and ask to see his/her liscense... There should be a letter B somewhere on the liscesne that means that the driver needs corrective lenses (glasses or contacts). If they are pulled over and found not to be wearing any, it's not good.

Perhaps, Shapeshifters are allowed to be given a license with a preferred face, but there is a special letter (Not S... that's School Bus Endorsement... And SS is probably gonna tick off people) that says the bearer of the license is a Shape Shifter. The officer could as for proof at which point the shapeshifter only needs to demonstrate a visible but minor change, not revert to the person in the photograph.

After all, ask anyone who has dyed their hair: You don't have to get a new license because your a brunette who wanted to try blonde.

The one admitted problem is shapeshifter identity theft where a bad shapeshifter can take a good shapeshifter's ID and claim to be the good one. This might be a problem if shapeshifters are not rare, but if not... hope your readers don't spot the problem... or steer into the skid and make it a problem.


I realise this answer reiterates some points in other answers, but the context is required.

The end goal of having any form of ID is to be able to be AUTHORISED to perform some action, whether it be driving a car with a driving licence or updating your StackExchange profile with your login details. Those are two very different actions, but follow the same principles of IDENTIFICATION, AUTHENTICATION and AUTHORISATION (albeit to very different degrees).

Identification for StackExchange is practically non-existent, you state who you are, you go through some steps to prove you're a human and job done. For something like a Driving Licence, the identification step is a lot more stringent, you have to provide other forms of ID like birth and marriage certificates (which are identity documents in their own right), etc..

So the AUTHENTICATION step is purely about proving you are the same individual who was IDENTIFIED in the first place.

There are 3 factors of AUTHENTICATION: - what you know - what you have - what you are

A username and password is something you know, a photo ID card is both something you have (the actual card) and something you are (the photo).

Buying alcohol with a driving licence is as all in one process, you are IDENTIFIED by your driving licence, you are AUTHENTICATED because you have it and you look like the photo on it and you are AUTHORISED because the date of birth on the card says you are over the required minimum age limit.

In the scenario where the a photo becomes untrustworthy, you have two choices. Move to another form of something you are (finger prints, voice pattern, DNA, etc.) depending what is still trustworthy, or move to something you know (password, pin number, signature, etc).

It all depends on how paranoid a society with shapeshifters is and how much they are willing to spend on infrastructure for both the IDENTIFICATION process (getting a DNA profile has an overhead, as does storing it on a chip on a card) and the AUTHENTICATION process (being able to take and process a DNA sample and match it to the known profile within a few seconds). That AUTHENTICATION process may need to be replicated at every convenience store in your country (and possibly surrounding countries too).

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    $\begingroup$ I have to wonder what the difference between AUTHENTICATION and authentication is xP $\endgroup$
    – jgon
    Commented Apr 8, 2019 at 15:19

Ids are paired with a passwords or pins. You ID says you are xxxxx, what is your password/pin, and the answer to 10 random questions about your past, to prove it?

Realistically a photo id will be of little use to shapeshifters. We have to accept that what works in our human society works because it was designed for the human condition. However a civilization composed of other kinds of organism probably wont follow the same cultural developments that we did.

So some other form of ID will be necessary if this is something the authorities are interested in pursuing.

At least up until the day of instant dna kits, then dna will be the identifier.


Assuming modern data connectivity - a shapeshifter could choose (or be assigned) some distinctive code phrase. When checking a shapeshifter's ID, a peace officer can run the ID through a scanner, then ask for the appropriate code from anyone carrying a shapeshifter ID.

"ISJ37, Officer."

Obviously, you would arrest anyone who couldn't give the correct code.

The downside would be that shapeshifters could easily impersonate each other, assuming the one being impersonated was willing to share his/her/its code. This code arrangement would also open them up to be more vulnerable to identity theft, at least by another shapeshifter... but those stinking 'Shifties' deserve whatever they get!

The real trick is being sure that someone isn't a shapeshifter. Heck, YOU could be one.


(Hello, everyone! New to this SE, let me know if I do anything stupid!)

I tried to structure this answer somewhat but didn't quite succeed. ;)

Obvious suggestions


There isn't necessarily a problem with passport like documents. They include a description of what you look like, which is worthless in the context of shapeshifters but they also include a signature which probably cannot be replicated by a shapeshifter and they are hard to forge so having one also carries some weight. And in the end, the system doesn't have to be perfect! Unless, maybe you're creating some sort of surveillance state. ;)


Assuming that there are certain parts of their physicality that shapeshifters cannot change, you can just implant a chip there. Most likely part would be the brain, I suppose. If you give it low enough range it would also be difficult to read it from anywhere but extremely close-up. (Current RFID/NFC tech has been read from several meters away in lab settings, can be easily stopped with some sort of RFC shield could be sold in the form of hats or wristbands or whatever would cover the place that holds the chip.) Depending on where you implant the chip it will also make it extremely difficult to remove the chip without killing the carrier. Which will foil some attacks.

Different approach, authentication factors


PINs, passwords, facts about your life... the three typical categories of authentication factors have already been introduced, for example in the answer by Tim B II. To use this, given a form of reasonably secure electronic ID (as widely used all over the world) you can ask for somebody's ID, put it in a terminal and ask them questions that only they should be able to answer. Using a PIN will work against most attacks but once it is known it is known. Giving some form of suitable surveillance technology you can also ask background questions that only the right person would know. Or something in between, like credit card companies asking you what the color of your last car was, etc. This is pretty easy to determine but somebody other than you might not have the answer available on the spot.


There are some biometric factors that a shapeshifter might not be able to change. For example there are gait recognition systems (determine who you are by looking at how you walk, see some Mission Impossible). Other people have already suggested DNA tests and other shapeshifter specific fictional things.


Photo IDs already perform this job as long as they are hard to fake. So maybe use some electronic passport and not US drivers licenses. ;) In addition to being hard to fake it should also be possible to revoke them when found missing and they should be required sufficiently often that loss will be noticed. They should also be linked to important things, like all your money and private data or something to make sure that people are unlikely to share them. (Like they do with payback cards.)



Don't base your actions on authentication when it is not necessary. If you catch a car with a broken tail light, simply fine the owner, not the driver.


You cannot single out the shapeshifters unless you at least have a method for detecting them. If you've ever watched DS9, a blood sample from a shapeshifter will turn into jelly, this gives a reliable way of detecting that somebody is or is not a shapeshifter. Then you can have special procedures for shapeshifters. If there is no way to distinguish them you need a system that works on everyone.


Photo ID might work, but only if your shapeshifter has unchangeable base form ("who they are") and it can be detected by authorities. They might have a special technology or magic that forces shapeshifters to revert to their base form, or the device that might be able to show/scan their base form.

Alternatively, you need to establish something unique that differentiates one shapeshifter to the other shapeshifter, even if they have the same unlimited capabilities to shapeshift. Such thing might be extraordinary:

  • soulprint
  • aura
  • true name

Of course, physical features are out of question; face, fingerprint, retina, iris, etc. However, depending on how your shapeshift ability works, you can put restriction on the shapeshift, something that can't be changed when you shapeshift, on which you can base your identification method. For example:

  • DNA
  • smell
  • an organ

These things might replace the photo in an ID, or complement it. Of course, the authority can detect these unchangeable thing and verify your ID using them.

  • $\begingroup$ This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - From Review $\endgroup$
    – bukwyrm
    Commented Apr 8, 2019 at 11:12
  • $\begingroup$ @bukwyrm see the last paragraph. The compatibility can be achieved using photo ID if the shapeshifter has an unchangeable base form, and it can be detected by authorities. $\endgroup$
    – Vylix
    Commented Apr 8, 2019 at 11:16

Smart ID

Using the latest technology in facial scans the smart ID's picture changes with the users age, style, and body modifications. I assume an ID like this would be useful for shapeshifter that wants a ID that's always up to date with their new choice of face.

The ID could function by having the surface be a tiny screen who's information is updated periodically and matched on the ID itself. Maybe you could use already made technology for credit/debit cards to physically acess the features of the card as well as using a tiny harddrive to store the information. To change the face it would be a manual change via a kiosk. So as long as your shapeshifters keep a "style" for long enough to go to a kiosk and update their ID they should be fine.


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