I’m creating an application in which users may optionally verify their identity using the Danish NemID system.
I’ve seen that Auth0 supports authentication with NemID through Criipto, which seems reasonable, but I’m unsure if Auth0 supports asking an existing user, who has already authenticated using one identity provider, to authenticate with a second identity provider.
I’ve found the documentation on User Account Linking, but from what I can see, this only supports linking two existing accounts together. I want users to be able to authenticate with other social identity providers, and then further authenticate with NemID, which doesn’t seem to match what account linking is used for.
How can I prompt an existing account, which has authenticated using e.g. Facebook, to also authenticate with NemID (and hopefully link these two “accounts”)?
This is possibly in the documentation somewhere, but I haven’t been able to find it.
I have two further questions, but I’m unsure if this is related to Auth0 or the NemID provider, being Criipto. I’ll take my chances and ask here first.
Criipto provides various legal information about the user, which is linked to their SSN and thus legally verifyable, will Auth0 provide this information as part of the identity metadata?
Are NemID identities unique? E.g. if account A further authenticates with NemID, and account B attempts to authuenticate with NemID using the same credentials, will the authentication attempt be rejected?
Thanks in advance.