External single signon solution on PeopleTools 8.51
For PT 8.51, Kerberos Authentication is supported which uses secret key cryptography to provide authentication between clients and servers. It is the desktop solution for single signon.
More information can be found in the following document:
E-SEC: Is Kerberos Authentication Supported in PT 8.51? (Doc ID 1292661.1)
E-SEC: PT 8.x How to get External Single Signon Solution to Work with PeopleSoft (Doc ID 617999.1)
PeopleSoft also provide the information on single signon between PeopleSoft and Oracle application which will be easily get configured by Oracle Access Manager. More details are at Home > PeopleBooks > PeopleTools 8.51 PeopleBook: Security Administration > Implementing Single Signon.