0 0 votes Computer Networks network-security + – hem chandra joshi 696 views answer comment Share Follow Print See all 3 Comments 3 3 Comments reply gauravkc commented Dec 15, 2017 reply Follow flag Third party companies like Verisign, DigiCert give a certificate which indicates trust. When you wish to do some secure communication with a website, if the website has (say a certificate issued by verisign), your computer will connect to verisign to show the certificate of the website, which is used for authentication. If you aren't familiar with public key cryptography, learn that first. Then, have a look at this short video https://www.youtube.com/watch?v=SJJmoDZ3il8 Google contents of certificate. Google Digital Certificate and have a look at Images section. CA stands for Certificate Authority (Companies that issue digital certificates) 1 1 replyShare gauravkc commented Dec 15, 2017 reply Follow flag By the way, why is the question tagged in Mathematical Logic? 0 0 replyShare hem chandra joshi commented Dec 15, 2017 reply Follow flag mistakenly !! 0 0 replyShare Please log in or register to add a comment.