What Is SSL (Secure Sockets Layer)? - ITU Online

What Is SSL (Secure Sockets Layer)?

person pointing left

Definition: SSL (Secure Sockets Layer)

SSL (Secure Sockets Layer) is a cryptographic protocol designed to provide secure communication over a computer network. It is the standard technology for keeping an internet connection secure and safeguarding any sensitive data that is being sent between two systems, preventing criminals from reading and modifying any information transferred, including potential personal details. SSL operates between a web server and a browser to ensure that all data transmitted remains encrypted and private.

This technology became the backbone of secure internet transactions, paving the way for online shopping, secure banking, and confidential communications. While SSL has been succeeded by Transport Layer Security (TLS), the term “SSL” is still widely used interchangeably with TLS.

Understanding SSL (Secure Sockets Layer)

The Role of SSL in Internet Security

SSL plays a critical role in internet security by enabling encrypted communication between web servers and clients, thereby ensuring that sensitive information like credit card numbers, social security numbers, and login credentials are transmitted securely.

How SSL Works

SSL encryption is initiated through a process known as the “SSL Handshake,” which occurs in milliseconds:

  1. SSL Certificate Request: The browser requests the server to identify itself.
  2. Server Sends SSL Certificate: The server sends its SSL certificate, including its public key, to the browser.
  3. Key Exchange: The browser verifies the certificate with the certificate authority (CA) and then creates, encrypts, and sends back a symmetric session key using the server’s public key.
  4. Secure Communication: The server decrypts the symmetric session key using its private key and sends an acknowledgment encrypted with the session key to start the encrypted session.
  5. Encrypted Data Transfer: From this point, all transmitted data is encrypted with the session key.

Benefits of Using SSL

  • Data Encryption: Ensures that data exchanged between the web server and browser is unreadable to anyone else.
  • Authentication: Verifies that users are communicating with the intended server, preventing man-in-the-middle attacks.
  • Data Integrity: Data cannot be modified or corrupted during transfer without detection.
  • Trust and Credibility: SSL certificates provide visual cues (like a padlock icon or green address bar), indicating that the website is secure and increasing user trust.

Types of SSL Certificates

  • Domain Validated (DV) Certificates: Verify the ownership of the domain.
  • Organization Validated (OV) Certificates: Validate the business that owns the domain.
  • Extended Validation (EV) Certificates: Require a thorough validation process and provide the highest level of trust, usually displaying the company name in the browser’s address bar.

Implementing SSL

To implement SSL, a website owner must obtain an SSL certificate from a Certificate Authority (CA). This process involves generating a public and private key pair and submitting a certificate signing request (CSR) to the CA. Once the CA validates the request and issues the certificate, it can be installed on the web server.


While TLS is the successor to SSL, providing stronger encryption algorithms and better security, the term SSL is still commonly used to refer to both protocols. Most modern systems use TLS, even when referring to the process as “enabling SSL.”

Frequently Asked Questions Related to SSL (Secure Sockets Layer)

What Is SSL (Secure Sockets Layer)?

SSL is a cryptographic protocol designed to provide secure communication over a computer network, ensuring that data transmitted remains encrypted and private.

How Does SSL Work?

SSL works through a process known as the SSL Handshake, which involves the exchange of SSL certificates and cryptographic keys to establish a secure encrypted connection.

What Are the Benefits of Using SSL?

Benefits include data encryption, authentication of the server’s identity, data integrity, and increased trust and credibility with users.

What Types of SSL Certificates Are There?

There are Domain Validated (DV) Certificates, Organization Validated (OV) Certificates, and Extended Validation (EV) Certificates, each offering different levels of validation and trust.

How Can I Implement SSL on My Website?

To implement SSL, obtain an SSL certificate from a Certificate Authority, generate a public and private key pair, submit a CSR, and install the issued certificate on your web server.

What Is the Difference Between SSL and TLS?

While SSL is the predecessor to TLS, the term SSL is still commonly used to refer to secure connections, even though most modern systems use TLS for enhanced security and encryption.

Is an SSL Certificate Necessary for All Websites?

While not technically necessary for all websites, an SSL certificate is strongly recommended for any site that handles sensitive information, as it ensures secure and encrypted communication.

Can SSL Prevent All Types of Cyber Attacks?

No, SSL encryption protects data in transit but does not safeguard against all types of cyber attacks, such as those targeting the website itself or the server it is hosted on.

LIFETIME All-Access IT Training

All Access Lifetime IT Training

Upgrade your IT skills and become an expert with our All Access Lifetime IT Training. Get unlimited access to 12,000+ courses!
Total Hours
2622 Hrs 0 Min
13,307 On-demand Videos


Add To Cart
All Access IT Training – 1 Year

All Access IT Training – 1 Year

Get access to all ITU courses with an All Access Annual Subscription. Advance your IT career with our comprehensive online training!
Total Hours
2635 Hrs 32 Min
13,488 On-demand Videos


Add To Cart
All-Access IT Training Monthly Subscription

All Access Library – Monthly subscription

Get unlimited access to ITU’s online courses with a monthly subscription. Start learning today with our All Access Training program.
Total Hours
2622 Hrs 51 Min
13,334 On-demand Videos

$14.99 / month with a 10-day free trial