SSL/TLS Certificate: What is it and Why You Need One

What is SSL?

What is TLS?

SSL vs TLS: What’s the Difference?

SSL certificate protocol - FACT

How SSL/TLS Certificates Work

HTTP vs HTTPS

ssl connection secure example
SSL certificate information

SSL or TLS Handshake

  1. Client greeting (hello)
    Client initiates handshake by sending a hello message to an SSL-certified website.
  2. Server greeting (hello)
    Server responds with the site’s SSL certificate.
  3. Authentication
    Client verifies the certificate
  4. Pre-master secret
    The client obtains a public key from the server’s SSL/TLS certificate, and then sends it back as an encrypted string of bytes.
  5. Decryption
    Server decrypts the public key (pre-master secret)
  6. Session Keys
    The client and server generate random session keys alongside the pre-master secret, which should receive the same results on both sides.
  7. Client and server ready
    Client and server both send encrypted “final” messages with session keys.
  8. Secure symmetric encryption achieved
    Handshake concludes and communication is continued via session keys.

Types of SSL Certificates

SSL Certificate Costs

Free SSL Certificate

Common SSL Certificate Errors

  • Your connection isn’t private: This happens when a browser can’t verify your domain’s SSL certificate. Because the browser can’t confirm the domain’s identity, it blocks the user from accessing the site.
  • Expired certificate: If you don’t renew your domain’s certificate before it expires, users will get an error message alerting them to the fact that your certificate is no longer valid.
  • Untrusted Certificate Authority: When this error is encountered, it means that the browser was unable to locate the root certificate from a trusted source. This can also happen if a certificate is self-signed and not added to a browser’s trusted store.

SSL Certificate Checker

SSL/TLS Certificates Recap

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Learn more about the Domain Name System (it’s not as hard as you may think), we post new blogs and educational infographics every week.