juurisertifikaattiin

A juurisertifikaattiin, or root certificate in English, is the foundational document in a public key infrastructure (PKI). It is a digital certificate issued by a trusted Certificate Authority (CA) that vouches for the identity of the CA itself. Essentially, it's the certificate that anchors the entire chain of trust for digital certificates.

Root certificates are self-signed, meaning they are signed by the CA that created them. This self-signing is permissible because the CA is inherently trusted by operating systems, web browsers, and other software applications. These applications come pre-loaded with a list of trusted root certificates from reputable CAs.

When a web browser encounters a website that uses an SSL/TLS certificate to establish a secure connection, it checks the certificate's validity. This involves tracing the certificate back through a chain of intermediate certificates until it reaches a root certificate. If the root certificate in this chain is present in the browser's list of trusted root certificates, the connection is deemed secure. If the root certificate is not trusted or has expired, the browser will display a warning to the user.

The security of the entire PKI system relies heavily on the security of these root certificates. If a root certificate is compromised, it could allow attackers to issue fraudulent certificates, impersonate legitimate websites, and intercept sensitive data. Therefore, CAs go to great lengths to protect their root certificates.