It is recommended not to use keys of sizes less than 1024 bits because of their insufficient strength. You can customize the size of EDH key with the system property jdk.tls.ephemeralDHKeySize. For information about how to customize the EDH key size for Access Manager components, see the following sections:
Administration Console: Section 2.12, Customizing the Size of EDH Keys
Identity Server: Section 3.12, Customizing the Size of EDH Keys