The SSL certificate

What is a security certificate? A SSL security certificate is a digital document issued by a Certification Authority that certifies the fact that the website in question is secure, recognized and safe. This security certificate is used to create a secure connection (encrypted) with the help of a protocol called Secure Sockets Layer. This ensure that the personal data used on certain sites, I don’t get in the hands of criminals or hackers. Using such a protocol is necessary for banking transactions or to protect data confidential. You can recognize a secure connection with this protocol by the fact that the website address begins with https:// instead of http://. Google Chrome displays a padlock green before the URL if the protocol is used.
There are many causes that underlie the problems with these security certificates, but the most common are:
The date, time or time zone incorrect
One of the most common causes is the fact that the date, time and time zone of the system do not correspond with the real ones. Be the date and time are in the future, whether they are in the past. SSL certificates being valid only over a limited period of time, these times are not yet valid or expire. If you have this problem, all browsers that you have in the system will display errors similar.
Another cause is fairly common for problems occur with security certificates is that the system is infected with a virus or a malware. This situation is quite dangerous, especially in the case of bank transactions. Viruses can change the keys of the certificate of security in order to hijack the connection secure it to steal confidential data. If the security certificate is inexplicably revoked on all sites that use the HTTPS protocol, then you can be sure that you have this problem. A problem less common is the firewall configured incorrectly. If you encounter an error similar to the one above, then you have this problem. Make sure that your firewall is not blocking TCP port 443 (used by HTTPS protocol).
The certificate is not signed by a recognized authority
Error meet more rarely and definitely not on all sites. Then when you meet this error means that the security certificate of that site is not signed by a Certification Authority recognized. SSL certificates can be generated for any person who has the necessary knowledge to do this or that needs a secure connection to private. This kind of certificate are called Self-Signed (signed by itself) and will always display these errors. If you do not know which website you want to visit and you receive this error it is advisable to leave him.