@node PAKE
@subsection Password Authenticated Key Agreement

GoVPN uses strong password authentication. That means that it uses human
memorable @strong{passphrases}, instead of some small high-entropy keys
that must be carried with himself. Passphrases differ from passwords:
they are long string of low-entropy characters -- they are easy to
remember and can have high overall entropy.

Strong zero-knowledge authentication means that:

@itemize
@item compromising of passphrase files on either server or client sides
won't allow attackers to masquerade himself the client;
@item no need of protected secure storage on the server's side to keep
keys in safety.
@end itemize

Passphrases are entered directly by the human on the client side. Server
side stores pre-shared @ref{Verifier, verifier}, containing dictionary
attack resistant passphrase derivative. Attacker can not use it to act
as a client.