Oracle E-Business Suite comes with native user authentication and management capabilities out-of-the-box. If you need more-advanced features, it's also possible to integrate it with Oracle Internet Directory and Oracle Single Sign-On or Oracle Access Manager, which allows you to link the E-Business Suite with third-party tools like Microsoft Active Directory, Windows Kerberos, and CA Netegrity SiteMinder. 
For details about third-party integration architectures, see either of these article for EBS 11i and 12:

• In-Depth: Using Third-Party Identity Managers with E-Business Suite Release 12
  
• In-Depth: Using Third-Party Identity Managers with the E-Business Suite Release 11i

Oracle Internet Directory 11.1.1.4 is now certified with Oracle E-Business Suite Release 11i, 12.0 and 12.1.  OID 11.1.1.4 is part of Oracle Fusion Middleware 11g Release 1 Version 11.1.1.4.0, also known as FMW 11g Patchset 3.  Certified E-Business Suite releases are:

• EBS Release 11i 11.5.10.2 + ATG RUP 7 and higher
• EBS Release 12.0.6 and higher
• EBS Release 12.1.1 and higher

Oracle Internet Directory 11.1.1.3.0 can be integrated with two single sign-on solutions for EBS environments:

• With Oracle Single Sign-On Server 10g (10.1.4.3.0) with an existing Oracle E-Business Suite system (Release 11i, 12.0.x or 12.1.1)
• With Oracle Access Manager 10g (10.1.4.3) with an existing Oracle E-Business Suite system (Release 11i or 12.1.x)