My take on PAKE: it's a way to establish a shared key (KE), authenticating each other with a password (PA). The shared key could then be used to build a secure

My take on PAKE: it's a way to establish a shared key (KE), authenticating each other with a password (PA). The shared key could then be used to build a secure channel. Believe it or not, I've seen many people thinking that KE alone is enough to build a secure channel. This misconception is probably as widespread as encryption provides message integrity. One needs to know he's talking to the right person, otherwise he's vulnerable to some man in the middle. There are many ways to solve this authentication problem. A large number of TLS ciphersuites uses PKI, but there are also ciphersuites using pre-shared key or password such as TLS-PSK or TLS-SRP. PAKE protocols use a password to authenticate each other, e.g., if only Bob could know the password he's the only one could finish the protocol with Alice. Recently I've worked on some authenticated key exchange problems not using a password, which could be fun to think about: 1) How to build a secure inter-app channel on iOS. 2) How to bootstrap keyboard-less devices to password-protected WIFI network.