Send GUID in custom ADFS claim rule

Question

Is it possible to send GUID (Active Directory field ObjectGUID) in ADFS custom claim rule as string like "00fecc2a-195e-4c88-a10b-981a6881fa00" and not encoded in base64 like "Ksz+AF4ZiEyhC5gaaIH6AA==".

<AttributeStatement>
    <Attribute Name="http://schemas.microsoft.com/identity/claims/objectidentifier">
        <AttributeValue>00fecc2a-195e-4c88-a10b-981a6881fa00</AttributeValue>
     </Attribute>
</AttributeStatement>

Answer 1

Yes - you can use an ADFS custom attribute store.

The code is as per the screenshot here.