Which of the following must the developer validate before the user data can be trusted?
The token’s nonce
The key ID in the token’s header
The token’s signature
The token’s issuer claim
Explanations:
The nonce is not a required field in a JWT, and its presence is more relevant for preventing replay attacks in specific contexts. Validating a nonce is not necessary for trusting user data from a Cognito JWT.
The key ID (kid) in the token’s header indicates which key was used to sign the JWT. While it is important for signature validation, it is not directly related to validating the trustworthiness of the user data itself.
Validating the token’s signature is essential for ensuring that the JWT has not been tampered with and that it was issued by a trusted source. This ensures the authenticity and integrity of the user data.
The token’s issuer claim (iss) is important for identifying the source of the token but does not directly ensure the integrity of the user data itself. It is a part of the validation process but not the sole determinant of trustworthiness.
I surmise that the answer is:
The token’s signature