Relying Party identifiers. The Relying Party is the website or application that relies on FIDO2 to authenticate users.

• name: The plain language name of the Relying Party.
• id: The RPID identifies the Relying Party. If an RPID is not set in the policy, its default value will be the effective domain of the origin of the caller who calls the Authenticator. The "id" can be set as the domain name of the Relying Party or the hostname of the Relying Party.

  If your company's DNS domain (or part of the FQDN of your website) is "shopping.com.in", then the optimal RPID would be "shopping.com.in" - and the FIDO Login page might be "login.shopping.com.in".

  If the domain name is used such as example.com, an Authenticator registered on app.example.com can also authenticate on app2.example.com. If the hostname of the RP is used—for example app.example.com—then an Authenticator registered on app.example.com will only be able to authenticate on app.example.com.