Deckard’s Front Door Key

I’m sorry. I could have sworn in advance that this would be a very quick post. One or two paragraphs.

  • Narrator
  • It wasn’t.

Exiting his building’s elevator, Deckard nervously pulls a key to his apartment from his wallet. The key is similar to a credit card. He inserts one end into a horizontal slot above the doorknob, and it quickly *beeps*, approving the key. He withdraws the key and opens the door.

The interaction…

…is fine, mostly. This is like a regular key, i.e. a physical token that is presented to the door to be read, and access granted or denied. If the interaction took longer than 0.1 second it would be important to indicate that the system was processing input, but it happens nearly instantaneously in the scene.

A complete review would need to evaluate other use cases.

  • How does it help users recover when the card is inserted incorrectly?
  • How does it reject a user when it is not the right key or the key has degraded too far to be read?

But of what we do see: the affordance is clear, being associated with the doorknob. The constraints help him know the card goes in lengthwise. The arrows help indicate which way is up and the proper orientation of the card. It could be worse.

A better interaction might arguably be no interaction, where he can just approach the door, and a key in his pocket is passively read, and he can just walk through. It would still need a second factor for additional security, and thinking through the exception use cases; but even if we nailed it, the new scene wouldn’t give him something to nervously fumble because Rachel is there, unnerving him. That’s a really charming character moment, so let’s give it a pass for the movie.


A small LED would help it be more accessible to deaf users to know if the key has been accepted or rejected.

The printing

The key has some printing on it. It includes the set of five arrows pointing the direction the key must be inserted. Better would be a key that either used physical constraints to make it impossible to insert the card incorrectly or to build the technology such that it could be read in any way it is inserted.

The rest of the card has numerals printed in MICR and words printed in a derived-from-MICR font like Data70. (MICR proper just has numerals.) MICR was designed such that the blobs on the letterforms, printed in magnetic ink, would be more easily detectible by a magnetic reader. It was seen as “computery” in the 1970s and 1980s (maybe still to some degree today) but does not make a lot of sense here when that part of the card is not available to the reader.


Also on the key is his name, R. DECKARD. This might be useful to return the key to its rightful owner, but like the elevator passphrase, it needlessly shares personally identifiable information of its owner. A thief who found this key could do some social hacking with the name and gain access to his apartment. There is another possible solution for getting the key back to him if lost, discussed below.

The numbers underneath his name are hard to read, but a close read of the still frame and correlation across various prop recreations seem to agree it reads

015 91077
VP45 66-4020

While most of this looks like nonsense, the five-digit number in the upper right is obviously a ZIP code, which resolves to Arcadia, California, which is a city in Los Angeles county, where Blade Runner is meant to take place.

Though a ZIP code describes quite a large area, between this and the surname, it’s providing a potential identity thief too much.

Return if found?

There are also some Japanese characters and numbers on the graphic beneath his thumb. It’s impossible to read in the screen grab.

If I was consulting on this, I’d recommend—after removing the ZIP code—that this be how to return they key if it is found, so that it could be forwarded, by the company, to the owner. All the company would have to do is cross-reference the GUID on the key to the owner. It would be a nice nod to the larger world.

(Repeated for easy reference.)

The holes

You can see there are also holes punched in the card. (re: the light dots in the shadow in the above still.) They must not be used in this interaction because his thumb is covering so much of them. They might provide an additional layer of data, like the early mechanical key card systems. This doesn’t satisfy either of the other aspects of multifactor authentication, though, since it’s still part of the same physical token.

This…this is altered.

I like to think this is evidence that this card works something like a Multipass from The Fifth Element, providing identity for a wide variety of services which may have different types of readers. We just don’t see it in the film.


Which brings us, as so many things do in sci-fi interfaces, back to multi-factor authentication. The door would be more secure if it required two of the three factors. (Thank you Seth Rosenblatt and Jason Cipriani for this well-worded rule-of-thumb)

  • Knowledge (something the user and only the user knows)
  • Possession (something the user and only the user has)
  • Inherence (something the user and only the user is)

The key counts as a possession factor. Given the scene just before in the elevator, the second factor could be another voiceprint for inherence. It might be funny to have him say the same phrase I suggested in that post, “Have you considered life in the offworld colonies?” with more contempt or even embarrassment that he has to say something that demeaning in front of Rachel.

Now, I’d guess most people in the audience secure their own homes simply with a key. More security is available to anyone with the money, but economics and the added steps for daily usage prevent us from adopting more. So, adding second factor, while more secure, might read to the audience as an indicator of wealth, paranoia, or of living in a surveillance state, none of which would really fit Blade Runner or Deckard. But I would be remiss if I didn’t mention it.

5 thoughts on “Deckard’s Front Door Key

  1. Does it make any sense to have the key card itself be something like a thumbprint scanner, such that the key is passing more than one type of data to the lock mechanism? Like – ‘I am the unique security card assigned to user:Deckard’ and ‘here is the thumbprint/pulse/pheromone pattern/DNA of the person using this card’.

    Wouldn’t this be two-factor authentication with a single action on the user’s part? It avoids you putting in a key and then touching another sensor or speaking a code phrase. It might also allow the sensor tech to change without replacing all the locks in the building.

    • That does make a great deal of sense. You would want to provide feedback for when the thumb was being well-read and when adjustments need to be made, and it certainly would greatly increase the cost of the key, but it would satisfy the multi-factor problem.

      • The key could be powered through the lock, like a USB device. A haptic signal, either from the key itself or transmitted through the key from a buzzer in the lock, could indicate a successful reading.

        One thought about the holes in the key: perhaps this is how the keys are given a unique identity. If the key has regions of detectable elements on it, and a keymaker punches out some set of them with punches of different sizes in different places, that could be the way to make the key unique without a mechanical pins-in-holes arrangement. Perhaps the card reader shoots a laser into the edge of the key and looks for a particular pattern of internal reflections generated by the holes. If the resolution is fine enough, and the key material is stable enough, it could be difficult to counterfeit. Or the punched-out sections could be sitting in the lock or in the super’s office in the basement, acting as the ‘private key’ to the rest of the card’s ‘public key’. The isotope ratios have to match, or the magnetic harmonics have to be compatible, or some such. Like a tally stick!

        Perhaps one punched bit is in his apartment’s security system, and another punched bit is at the evidence locker at work, etc.

  2. Pingback: Report Card: Blade Runner (1982) | Sci-fi interfaces

  3. I should just point out that nearly every hotel room door in every posh hotel has a door lock made by one of two manufacturers, and follows this exact form factor. And yes, they are often a pain. They use magstripes, and they get killed by high powered magnets on phone cases, and often take a few tries to read.

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