Recently, I try to read some papers about Password Authenticated Key Exchange (PAKE). I can’t understand the meaning of “dummy password .” Can someone gives a concrete definition of it. And what is the difference between password and dummy password?

The context for this question is the following sentence:

then, we modify the protocol so that $\pi$ in $y$ is a dummy password

  • 1
    $\begingroup$ There the dummy is a random password to foil the attacker. $\endgroup$
    – kelalaka
    Commented May 2, 2020 at 13:02
  • $\begingroup$ I'm afraid the definition is specific to the context of the paper, I've not heard it in general usage (it might still be common in papers about PAKE, I must admit, I have certainly not read all of them). $\endgroup$
    – Maarten Bodewes
    Commented May 2, 2020 at 14:31
  • $\begingroup$ 1234... just kidding! $\endgroup$ Commented May 3, 2020 at 16:32

1 Answer 1


It appears this term is only used in the proof. In this context "dummy password" is to be understood as
"some value that syntactically fits the requirements of a regular password including matching the length of the replaced password but is not actually the password to be used in this exchange".
The point here is that an adversary cannot distinguish between the actual password being contained in a value and some other "fake password" being contained in a value which then allows one to argue that an adversary learns nothing about the password given that they can't even tell whether the real one is used thus helping in proving that the exchange leaks nothing about the value of the password.


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