As you have already done the short and thick answer, I will do the long.
To understand the terms 'public key' and 'private key' you need to know a bit about encryption algorithms.
Introduction to Encryption
Encryption algorithms aim to ensure that a sender changes a message with a recipient without intermediaries getting it.
On the Internet, they are responsible for preventing strangers from reading your precious personal data. After all, you do not want people sneaking your email or worse, your credit card number!
There are two main ways to do this.
Symmetric algorithms use a single key, known in advance by both the sender and the recipient. The workflow is simple: the sender encrypts the message using the key and sends encrypted content over the internet. The receiver then receives the message and decrypts it using the same key.
As you may have noticed, this kind of algorithm has a problem: both sides of the conversation need to know what the key is to decrypt the message! How to send secure messages to unknown recipients? Simple.
Asymmetric algorithms work not with one but two keys:
- A public key , available to everyone, is used to encrypt the message. This key can not decrypt .
- A private key , known ONLY by the recipient, has the power to decrypt messages.
Asymmetric algorithms work (almost) as mailboxes: Any sender can put (encrypt) a message in his box, but only you, the recipient, can read.
Regarding the topic of the question
What do each of these two types of keys mean?
I hope the above explanation has answered.
Why are they used in SSL certificates
Certificates are a form of asymmetric algorithm. When you want to send something important to a site, you first encrypt your data using the site's public certificate. This ensures that only the owner of the site can read your information.
Does a private key have any relation (a dependency relation, for example) with the public key?
Well, to encrypt something you need the public and to decrypt the private. It does not make much sense to have one without the other.
They follow some pattern (since I always see these keys with code similar to a base64)?
There are several certificate standards. A very common example is X509 . All the standards I know for certificates are binary, for performance.
What are the standard file extensions to identify each of them?
There are several different extensions for certificates. If you understand English I suggest you take a look at this . > blog.
Other Questions
Are both the private key and the public key encoded in X509?
Yes.
