mTLS client cert
also: client certificate, mutual TLS certificate, mTLS cert
A client certificate used in mutual TLS (mTLS) authentication, where the client proves its identity to a server by presenting a digitally signed certificate in addition to verifying the server's certificate.
mTLS client cert is an X.509 certificate presented by a client application during a TLS handshake to authenticate itself to a server. In standard TLS, only the server proves its identity; with mTLS (mutual TLS), both parties authenticate each other bidirectionally.
The client certificate contains the client's public key and metadata, signed by a trusted certificate authority (CA). The server validates this certificate by checking the CA signature and ensuring the certificate hasn't been revoked, establishing trust in the client's identity.
Example: A microservice in a Kubernetes cluster uses an mTLS client cert to connect to another service. The client presents /etc/certs/client.crt and /etc/certs/client.key, and the server verifies the certificate before allowing the connection.