OpenID implementation. Is there anything unique to user identification?

Question

I would like to implement user authentication using OpenID.

Is there something unique in user data that OpenID provides that I could use as a key to remember and identify users? I was thinking about using email, but the user could change it.

Answer 1

An OpenID user ID is what you should use for this purpose.

This is either a URL entered as an identifier, or returned as claimed_idwhen available. In any case, in fact, retain your identity only after successful authentication.

7.2 7.3 OpenID 2.0 .

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