+.B srp-interval \fIn
+If this parameter is given and pppd uses EAP SRP-SHA1 to authenticate
+the peer (i.e., is the server), then pppd will use the optional
+lightweight SRP rechallenge mechanism at intervals of \fIn\fR
+seconds. This option is faster than \fBeap-interval\fR
+reauthentication because it uses a hash-based mechanism and does not
+derive a new session key.
+.TP
+.B srp-pn-secret \fIstring
+Set the long-term pseudonym-generating secret for the server. This
+value is optional and if set, needs to be known at the server
+(authenticator) side only, and should be different for each server (or
+poll of identical servers). It is used along with the current date to
+generate a key to encrypt and decrypt the client's identity contained
+in the pseudonym.
+.TP
+.B srp-use-pseudonym
+When operating as an EAP SRP-SHA1 client, attempt to use the pseudonym
+stored in ~/.ppp_psuedonym first as the identity, and save in this
+file any pseudonym offered by the peer during authentication.
+.TP