Thank you for posting this in Microsoft Q&A.
I Understand you are trying to authenticate a user using certificate flow in Azure OAuth 2.0. you are specifically looking for information on how to generate a client assertion for authentication.
How can I generate client assertion for authenticate user.
To obtain a client assertion to authenticate the user, I am referring to this post where a similar issue has been discussed: https://learn.microsoft.com/en-us/answers/questions/1388776/how-to-get-access-token-using-certificate-based-au. Please follow the post and let me know if you are facing any issues.
To request an access token with a certificate credential, use an encoded token as client-assertion.
Thanks,
Navya.
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