When we talk about certificate, very first image comes to our mind is some sort of degree certificate. You generally given hard copies of these certificates during school, college time.
Question comes, is this the digital certificate ?.
Yes, kind of but digital certificate has lot many other things, let's understand.
What is Digital Certificate ?
Digital certificate is electronic document that identify any person, company or any entity. This is similar to your identity card which is being issued to identify you.
Let's take one example, when you join any professional organization, an identify card is issue to you that has name, date of birth and employee number and other details.
You are not allowed to enter the organization premises in case you don't have that identity card so this card act as your identity in the organization and anyone can recognize you from that card.
Same way Digital Certificate is electronic document that hold set of attributes related to holder of certificate. That attribute is your name, a serial number, expiration dates, a copy of the certificate holder's public key.
The most common type of certificate is the one compliant with the X.509 standard.
Below is one of the example.
Can I create my own digital certificate ?
No, you cannot create it on your own. You have to purchase it from the authorized Certificate Authorities (CAs), like Symantec, RapidSSL, Comodo, GeoTrust or else you can even buy it from their re-sellers such as The SSL Store™.
Who issue digital certificates ?
As mentioned above, Digital certificates are issued by certificate authority. As you can see in below picture,
Issue to: refer the person or entity.
Issue by: refer to the certificate authority who issue the certificate.
What is use of digital certificate ?
Since you understand about digital certificate now the question comes on the use of it. Let's understand that.
Main purpose of Digital certificates is to send data securely to other parties.
Let's take one example to understand it.
Joe want to send business message to one of his client Mark . Since this is business message so Joe want to make sure Mark gets the message from him only as other competitors can fake the identity and try to send the message to Mark on behalf of Joe to steal his business.
To avoid this situation, Joe use his digital certificate along with business message so that Mark comes to know that message from Joe only instead of receiving it from fake Joe.