Certificate management

Certificate management connects identity, trust, and cryptography. An X.509 certificate binds a public key to an identity, such as a DNS name, through a certificate authority's signature. During a typical TLS connection, the client validates the certificate chain, checks the requested hostname against the certificate's subject alternative names, checks validity dates, and verifies that the server controls the corresponding private key. The certificate is not secret; its private key must remain protected. A valid certificate alone does not require encryption or determine which TLS versions a server accepts.

The lifecycle starts with identifying endpoints, owners, trust requirements, and supported algorithms. Public-facing applications generally need certificates chaining to a publicly trusted authority. Internal applications can use a private certificate authority, but their clients must receive and trust the appropriate root certificates. Issuance controls should verify domain ownership or workload identity and restrict who can request certificates for sensitive names. Mutual TLS adds client certificate authentication, requiring management of both server and client identities.

Deployment must be paired with transport enforcement. For example, an AWS Application Load Balancer can use an HTTPS listener with an AWS Certificate Manager certificate and a security policy that permits approved TLS protocol versions and cipher suites. An HTTP-to-HTTPS redirect helps normal users, but the initial HTTP request remains unencrypted. Where cleartext connections are prohibited, do not expose an HTTP listener. For services such as object storage, use supported resource-policy conditions to deny requests that do not use secure transport.

Consider every network segment separately. TLS termination at a load balancer protects the client-to-load-balancer connection, not automatically the connection to application targets. Configure HTTPS targets when that segment also requires encryption. Encryption and authenticated peer identity are separate requirements: Application Load Balancers do not validate target certificates, so HTTPS targets alone do not establish validated backend identity. Applications with stricter identity requirements need an architecture that performs the required certificate validation.

Renewal must include successful deployment, not merely issuance of a replacement. Managed services can renew eligible certificates and update supported integrations, but imported certificates require a separate renewal process. Certificates deployed to application hosts need automation to distribute replacements and reload processes safely. Track expiration, renewal failures, certificate attachments, and ownership. For compromised keys, replace the key and certificate, revoke the old certificate where supported, and consider whether clients actually check certificate revocation lists or Online Certificate Status Protocol responses.

Regional scope also matters. AWS Certificate Manager certificates are regional resources; regional load balancers need certificates in their own Regions, while CloudFront viewer certificates managed by ACM must be in US East (N. Virginia). Plan issuance or supported import workflows for each required Region rather than assuming certificates replicate automatically. Private certificate authorities also require explicit regional availability and recovery planning.

Certificate keys and data-encryption keys serve different purposes. AWS KMS customer managed keys provide cryptographic operations and access controls, but they do not replace a certificate authority or issue TLS certificates. KMS multi-Region keys are related keys with shared key material, not a mechanism for replicating certificates or private CA resources. Automatic rotation of a symmetric KMS key does not renew a TLS certificate. Managed key custody reduces exposure and operational work, while portable key material increases deployment flexibility but also increases the burden of secure distribution, access control, auditing, and compromise response.