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An authentication is the action word for "to authenticate".

"To disauthenticate" and "to unauthenticate" do not seem to exist (I might be wrong).

So what is the most appropriate opposite action of an authentication ?


As more precision has been requested, I'm more searching a name for the act of reversing/canceling an authentication. Think of it as comparable to the Login/Logout, Sign In/Sign Out, etc. but I want one with "Authenticate / ?"

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@Drax Could it be de-authenticate? – WS2 Jan 8 '14 at 10:37
If you already googled, please let us know. – mplungjan Jan 8 '14 at 10:48
What do you mean by an "opposite" here? To erroneously authenticate? To reverse an authentication? To have no authentication requirements at all? – J.R. Jan 8 '14 at 11:21
@Drax: In most contexts, the best single word to mean "reverse an authentication" would be invalidate. If you insist on sticking with the same base word, disauthenticate would always be understood, but it's not a very "nice" word (i.e. - although other people sometimes use it "faut de mieux", mostly they don't). – FumbleFingers Jan 8 '14 at 12:19
de-authenticate - google has 8mio compared to 18K of disauthenticate and even asks "did you mean de-authenticate" – mplungjan Jan 8 '14 at 15:35
up vote 9 down vote accepted

Authentication is seen as "entering the state of being authenticated." An opposite of authentication would essentially mean "entering the state of being unauthenticated". It is more common to refer to the specific process used and the specific context would determine the most appropriate variant. A few examples:

Your session is about to expire.

This certificate is no longer valid — it is has been invalidated.

You have been logged out.

This painting is no longer for sale because the authentication has been retracted; its authenticity is suspect and if it is a forgery it will be exposed.

Your credentials have been compromised. Please authenticate.

If you truly need to refer to a specific opposite than the two most logical words would be:

  • unauthenticate
  • deauthenticate

You can read more about the un- versus de- differences here on EL&U. It is worth noting that "deauthenticate" seems to be more common while "unauthenticated" is already a word and sets a precedence for using "un-".

In the end, if you will be using the word for any official documentation or publicly facing content you should check with your employer and manager for any official style guides. There is no one correct answer, here, and consistency is very important.

One last note is that the term "reauthenticate" has a similar problem but can be avoided by simply using the word "authenticate." Certain dictionaries do include an entry for "reauthenticate", however. I was not able to find a dictionary that included either "unauthenticate" or "deauthenticate."

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This is definitely the complete answer i was waiting for, thanks :) – Drax Jan 9 '14 at 9:10

Try repudiate (repudiation), meaning "to reject the validity or authority of; to refuse to recognize; to cast off or disown (a son, lover, etc)"

The third definition there hints at the meaning of refusing to acknowledge the continuing existence of something (a relationship, for example) that existed at some other time.

Synonyms include rescind, countermand and invalidate.

You could say something like "Your credentials are hereby repudiated."

Repudiation is a data security term, described here:

Repudiation: A repudiation threat involves carrying out a transaction in such a way that there is no proof after the fact of the principals involved in the transaction. In a Web application, this can mean impersonating an innocent user's credentials. You can help guard against repudiation by using stringent authentication. In addition, use the logging features of Windows to keep an audit trail of any activity on the server.

I would take the repudiation of credentials to mean that any future transactions would be considered unauthenticated and repudiable.

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It doesn't really have one.

As an adjective I might use "unauthenticated". e.g. "You are unauthenticated". But it doesn't exist as a verb.

cf.: http://thesaurus.com/browse/authenticate

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Unauthenticated would usually mean "not yet authenticated", rather than "no longer authenticated". But the question is not clear as to which is required. – Andrew Leach Jan 8 '14 at 10:38
Agree; a good clarification. – MartinSGill Jan 8 '14 at 10:43
Andrew's observation is dead-on, but I see that as more of a problem with the O.P.'s question than with your answer. The O.P. hasn't even described what kind of "antonym" he is looking for. The antonym for "light" can be "dark" – or it can be "heavy", depending on what you are trying to say. – J.R. Jan 8 '14 at 11:19
@J.R. the word "antonym" was my (erroneous) correction/interpretation. He needs the OPPOSITE of authentication, i.e. the word for removal of a previously given authentication – mplungjan Jan 8 '14 at 12:26
I am not sure I can imagine how that works... revoking authorization, yes. But authentication is an identification. In order to make sure you remove authentication from a previously authenticated entity, you would have to make sure that you are dealing with the correct entity - meaning you need to authenticate. If authentication fails on that instance, you cannot remove earlier authentication. If authentication succeeds, however, you have just established that the earlier authentication should be regarded as valid. – oerkelens Jan 8 '14 at 13:54

I guess there is no exact antonym for the word authentication, but the following words can be considered as antonym (since authentication is ~ to approving, allowing, validating etc.)

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Allow me to expand things a bit. We needed a word for this because some drawings in our collection that were attributed to Frederic Remington turned out to be fakes after an inspection by the Buffalo Bill Museum, and we wanted to correct the catalog record. We felt really iffy about "de-authenticated" and so I googled that, and came here. After reading this page and the comments, we came up with this:

"This item was formerly attributed to Frederic Remington until 2014, when its authenticity was invalidated by the Buffalo Bill Museum in Cody, Wyoming."

I actually think I like "disauthenticated" the best, but I'm really weird. Thanks for your time!

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I frequently work on software projects which require authenticating users. It is not uncommon to hear someone say "deauthenticate" (frequently also written as "de-authenticate") when referring to revoking someone's authentication. It's even more common to hear simply "de-auth", and at least in context the meaning would be quite clear.

Staying in the tech world, the official IEEE 802.11 (for the non-techies, that's your WiFi) specification uses the word as the name for a specific type of datagram frame.

EDIT: I'd agree with the comments about "unauthenticated" referring to someone who has not yet been authenticated, as opposed to having had their authentication revoked. At best, it would be ambiguous.

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If you're looking to take something from previously proven to disproven, well, you may:

disprove it, debunk it, dislodge it, or discredit it. Similarly, something held to be true may be falsified, refuted, negated, or invalidated.

You prove it false, it may be an example of a false-positive or counterfeit even. You can shoot it down, blow it out of the water, or poke holes in it.

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"Authentication" does not carry the same meaning as "proof" in this context; this answer is not appropriate for this question. – acidnbass May 19 at 20:23

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