Abstract: A secure client authentication system may generate short-term x509 end-entity certificates and short-term private keys based on client-specific parameters and an expiration time. An x509 Certificate Authority (CA) may issue the short-term x509 certificates upon receiving a client request to access a secure endpoint. Each issued certificate may include a Time-To-Live (TTL) value that defines a limited validity period, facilitating ephemeral access to the secure endpoint. Automatic expiration of these access credentials may restrict to the secure endpoint beyond the limited validity period, enhancing security by mitigating risks associated with long-term static credentials.