You deploy an API to API Management You must secure all operations on the API by using a client certificate. You need to secure access to the backend service of the API by using client certificates…

Azure AD tokens are used for OAuth 2.0 or OpenID Connect authentication, which is a token-based mechanism, not certificate-based authentication.

Self-signed certificates can be used for client authentication in Azure API Management, particularly in development, testing, or internal-only scenarios where a trusted third-party CA is not required.

Certificate Authority (CA) certificates provide a higher level of trust and are standard for production environments, enabling robust mutual TLS authentication for both API consumers accessing the API Management gateway and the gateway accessing the backend service.

Triple DES (3DES) is a symmetric encryption algorithm used for data confidentiality, not for client certificate authentication or identity verification.

Subscription keys in API Management are used for access control at the API Management layer and are distinct from client certificate-based authentication.