selfsigned

Self-signed refers to a certificate whose digital signature is created with the private key of the same entity that owns the certificate, rather than by a trusted external certificate authority (CA). In practice, a self-signed TLS/SSL certificate is issued by the server itself.

Use cases for self-signed certificates include development, testing, internal services, and offline environments where acquiring a publicly trusted certificate is unnecessary or impractical. They enable encrypted connections without external verification, helping to validate the confidentiality of data in transit within controlled settings.

However, self-signed certificates present notable limitations. Web browsers and many clients do not trust them by default, leading to security warnings or blocked connections for public services. They do not provide a third-party endorsement of the server’s identity, making them more susceptible to impersonation if misused. There is also no built-in mechanism for revocation or public transparency, unlike CA-signed certificates.

Creation typically involves generating a private key and creating a certificate that is signed with that same key. Common tools like OpenSSL are used to generate the key and the certificate, specifying subject details and a validity period. For servers, the certificate and key are installed and configured on the service to enable HTTPS, with the understanding that clients will not trust the certificate unless the self-signed root is explicitly installed.

Best practices include keeping the private key secure, using short validity periods, and, for production or public-facing services, obtaining a certificate from a trusted CA or operating a private CA for internal trust. Self-signed certificates can be appropriate in isolated environments or as a step in development, but they are not a substitute for publicly trusted certificates in general deployment.