Why are Certificates more secure than Secrets?

Hello @DANILO BATISTA DE QUEIROZ , the main reasons of why Certificates are more secure than Secrets would be:

1. Certificate assertions are usually short-lived (Eg. 5 to 10 minutes) so if even if intercepted they will provide only limited use. Secrets on the other hand tend to be long-lived.
2. Secrets are symmetric keys so both client and server need to know about it. With certificates only the client needs to be able to use the private key w/o reading it (which is usually handled by the OS cryptographic system) while the server only needs to know the public key for validation thus you won't need to transmit/share the private key/secret. With a secret you will have to both share and transmit it.

Access tokens are usually short-lived (max 1 hour by default). Secrets, again, are usually long lived. Also, access tokens are issued to only 1 client while a secret can be used to issue several access tokens for several clients.

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