There are 45 questions tagged ; nearly all of them are also tagged either , , or , or tagged with a specific scheme like —see search for exceptions.

The standard security property of MACs and signatures is unforgeability under chosen-message attack, which is entailed by authenticated encryption, so the concept of ‘forgery’ is implied by the alternative tags.

What purpose does the tag serve? Should we delete it?

  • $\begingroup$ Perhaps you might want to reconsider this sentence: "...every one of which is also tagged either 'mac' or 'signature'." A quick look at the tags shows that many are not tagged with anything close. One is simply tagged "forgery". I counted nine which are not tagged with "mac" or "signature" or anything directly related. Then I stopped counting. In point of fact, we see quite a variety of tags used with "forgery". This is not at all to belie the question itself. $\endgroup$
    – Patriot
    Sep 29, 2019 at 1:43
  • 1
    $\begingroup$ You're right; I did the search wrong. $\endgroup$ Sep 29, 2019 at 1:47
  • $\begingroup$ So are the ones not tagged signature or MAC still about signature or MAC or about something different? And if different, are there any questions purely about forgery (this seems unlikely as forgery requires something to be forged) or can we easily apply other tags? $\endgroup$
    – Maarten Bodewes Mod
    Sep 29, 2019 at 13:41
  • $\begingroup$ @MaartenBodewes Updated with a clearer search for exceptions. $\endgroup$ Sep 29, 2019 at 21:45

2 Answers 2


We should delete in favor of and .


We should keep because…

Fill me in, Community!

  • $\begingroup$ We should keep because not every question on MACs and signatures are about forgery. This can help to search. $\endgroup$
    – kelalaka
    Sep 30, 2019 at 17:07
  • $\begingroup$ Can you expand on that? For example, show a substantial number of questions that are about MACs or signatures but somehow don't involve forgery? Expand on why someone would watch a forgery tag but not MAC or signature tags? $\endgroup$ Sep 30, 2019 at 17:13
  • $\begingroup$ Interestingly this nice terminology question has no forgery tag. $\endgroup$
    – kelalaka
    Sep 30, 2019 at 17:14
  • $\begingroup$ There are questions containing HMAC but not about forgery, you will see that if you search secure HMAC that doesn't include forgery tag. This search secure HMAC -[forgery] excludes forgery contains 762 results, but secure HMAC is 762. The intersection is two questions. Your second point is great, and there is only 1 watcher. $\endgroup$
    – kelalaka
    Sep 30, 2019 at 17:48
  • $\begingroup$ HMAC is a PRF construction, so that's to be expected if the questions are not about its antiforgery properties but rather about its more general pseudorandomness. $\endgroup$ Sep 30, 2019 at 18:38

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