A processor-implemented system and method for dynamically retrieving an attribute value of an identity claim for a user using a digitally signed access token that is digitally signed by a user device, at a relying party device associated with a relying party. The method includes (i) making an API call to retrieve at least one identity claim for the user, (ii) processing each identity claim of the user, with the relying party device, to identify if at least one by-reference identity claim that includes a URL of an endpoint, (iii) obtaining the digitally signed access token that is digitally signed by the user device, (iv) invoking the URL of the endpoint with the at least one by-reference identity claim and the digitally signed access token, and (v) dynamically retrieving the attribute value from the URL of the endpoint from an issuing party device associated with an issuing party.