SAP NetWeaver PI allows for Single Sign-On through SAP Logon Tickets1 and x.509 certificates. Certificates allow for the usage of Secure Network Communications (SNC) and Secure Sockets Layer (SSL).
Single Sign-On Configuration - Procedure for PI Web Components http://help.sap.com/saphelp_nwpi71/helpdata/en/32/1c1041a0f6f16fe10000000a1550b0/frameset.htm ↩