I am started working in post quantum cryptography(lattice based cryptography) specifically in Password Authenticated Key Exchange (PAKE). I come across many PAKE key exchange scheme (like this one) that do not take in consideration the registration process and login process. These schemes simply assumes that two parties are sharing some secret password of low entropy and based on that they will generate common session key. So, my question regarding PAKE techniques are

What is the scope of PAKE schemes? Is Registration or Login process should not be considered while designing the PAKE key Exchange schemes?

  • $\begingroup$ I have started a chat related to cryptanalysis of key exchange given by Ding et al. based RLWE. Please see it here chat.stackexchange.com/rooms/62701/pake-based-on-rlwe $\endgroup$ – vivek Jul 24 '17 at 5:21

The definition of PAKE just suggests that one or more parties are exchanging keys with knowledge of a shared password that authenticates the exchanged key. There are definitely use-cases of PAKEs that extend beyond, say, a web application authentication process that requires registration. For example, there could exist two or more embedded systems with shared passwords built into the firmware during manufacturing but these systems want to exchange fresh keys for communication. There are PAKEs that do cover registration (e.g. SRP), but the "definition" of a PAKE does not really require a specification for a registration process.

Personally, I think PAKE authors should specify a password bootstrapping process, if possible! It could prevent implementors from rolling-their-own protocol extensions.

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  • $\begingroup$ What is password bootstrapping process $\endgroup$ – vivek Jul 3 '17 at 6:16
  • $\begingroup$ It very difficult to analyze security of the key exchange schemes without the knowledge of how communication starts. $\endgroup$ – vivek Jul 3 '17 at 6:18
  • $\begingroup$ For example in the above paper link given, I have to assume that the users get registered and then they starts the key exchange process using above technique. So security analysis become difficult. Thanks $\endgroup$ – vivek Jul 3 '17 at 6:21

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