Question

When browsing a web site, we see the following message. What does it mean that the certificate is not issued by a trusted CA? What is considered as a trusted CA? There is a problem with this website’s security certificate. The security certificate presented by this website was not issued by a trusted certificate authority.

Answer 1

GIVEN THAT:

The web browser shows the message CERTIFICATE IS NOT ISSUED BY A TRUSTED CA means,

*For every website you visit there is one provider who is issue the digital certificate. All the browsers having the Built-in list of trusted certificate provider.

*When we browse one website, the browser gets the certificate provider for that website and it will verify whether that provider is in the browser in-built trusted certificate provider list.

*If that provider is there in browsers in built list then it will now through any message.

*If in case the website digital certificate provider is not in the browser in built trusted certificate provider list then it will through the message CERTIFICATE IS NOT ISSUED BU TRUSTED CA.

*here CA is CERTIFICATE AUTHORITY which acts as third party entity who is issue the digital certificate for the website. The  digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others to rely upon signatures made about the private key that corresponds to the certified public key.

*The Trusted Certificate is used to establish the secure connections to the server.

*This message will show differently in different browsers.

Internet Explorer: "The security certificate presented by this website was not issued by a trusted certificate authority."

Firefox 3: "www.examplewebsite.com uses an invalid security certificate. The certificate is not trusted because the issuer certificate is unknown." or "www.examplewebsite.com uses an invalid security certificate. The certificate is not trusted because it is self signed."