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
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.
