SSL certificates are extensions that makes websites move from HTTP to HTTPS, which is more secure and better. An SSL certificate is a data file hosted in a website’s origin server. SSL certificates are data that makes SSL/TLS encryption possible, and they contain the website’s public key and the website’s identity, along with any other related information. Devices trying to communicate with the origin server will have to reference this file in order to obtain the public key and verify the server’s identity. The private key is kept secret and secure.
What is SSL?
SSL commonly called TLS, is a protocol for encrypting Internet traffic and verifying a server’s identity. Any website with an HTTPS web address uses SSL/TLS.
What information does an SSL certificate contain?
SSL certificates contains the following:
- The domain name that the certificate was issued for,
- The person, organization, or device it was issued to,
- The certificate authority that issued it,
- The certificate authority’s digital signature,
- Any associated subdomains,
- Date the certificate was issued,
- Date the certificate will expire,
- The public key (the private key is kept secret).
The public and private keys that are used for SSL are long strings of characters used for encrypting and decrypting data. Any data encrypted with the public key can only be decrypted with the private key, and vice versa.
Reasons websites need an SSL certificate
A website needs an SSL certificate in order to keep its user data secure, verify they own the website, ensure attackers don’t create a fake version of the site, and gain its user trust. Here are some of the reasons:
Encryption: SSL/TLS encryption is possible due to the public-private key pairing that SSL certificates facilitate. Clients (such as web browsers) get the public key necessary to open a TLS connection from a server’s SSL certificate.
Authentication: SSL certificates verify that a client is talking to the correct server that actually owns the domain. This will help prevent domain spoofing and other forms of attacks.
HTTPS: Most crucially part for businesses, an SSL certificate is important for an HTTPS web address. HTTPS is the secure form of HTTP, and HTTPS websites are websites which have their traffic encrypted by SSL/TLS.
In addition to securing user data in transit, HTTPS makes sites more trustworthy from a user’s perspective. Many users won’t notice the difference between an http:// and an https:// web address, but most browsers have started tagging HTTP sites as “not secure” in more noticeable ways, attempting to provide incentive for switching to HTTPS and increasing security.
How does a website obtain an SSL certificate?
For an SSL certificate to be verified as been valid, domains have to obtain it from a certificate authority (CA). A CA is an organization, a trusted third party, that generates and gives out SSL certificates. The CA will digitally sign the certificate with their own private key, allowing client devices to verify it. Most, but not all, CAs charges a fee for issuing an SSL certificate.
Once the certificate is issued, it has to be installed and activated on the website’s origin server. Web hosting services usually handle this for website operators. Once it has been activated on the origin server, the website will be able to load over HTTPS. All traffic to and from the website will be encrypted and secure.
What is a self-signed SSL certificate?
Anyone can create their own SSL certificate by generating a public-private key pairing and inputting all the information mentioned above. This kind of certificates are called self-signed certificates because the digital signature is used, instead of being from a CA, would be the website’s own private key. No outside authority verifies them, so most browser still sees them as “not secure”, thus terminating the connection.
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