Hi @andrewz ,
Thanks for reaching out and thank you for your time and patience.
Unfortunately, Azure AD B2C doesn't create or transform HMACSHA254 token.
Also, it is not possible to do transformations on the resulting token. Claim transformation will only apply to claims in the claims bag.
You can post this idea at the Azure Feedback Portal, which is monitored by the product team for feature enhancements.
Hope this will help.
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