SSL (Secure Sockets Layer)

https://www.cloudflare.com/en-ca/learning/ssl/what-is-ssl/

SSL (Secure Sockets Layer) Overview

• SSL is an encryption-based security protocol developed by Netscape in 1995.

• Ensures privacy, authentication, and data integrity in online communications.

• SSL is the predecessor to TLS (Transport Layer Security), the modern encryption standard.

How SSL/TLS Works

1. Data Encryption:

   • SSL encrypts data transmitted over the internet, making intercepted data unreadable.

2. Authentication:

   • SSL initiates a handshake process to verify the identity of both communicating devices.

3. Data Integrity:

   • SSL digitally signs data, ensuring that it hasn’t been tampered with during transmission.

Importance of SSL/TLS

• Originally, data was transmitted in plaintext, vulnerable to interception.

• SSL encrypts sensitive information (e.g., credit card numbers) to prevent theft.

• Authenticates websites to avoid phishing attacks and ensures data isn’t altered.

SSL vs TLS

• TLS (Transport Layer Security) is the updated version of SSL, introduced in 1999.

• SSL 3.0 (last version of SSL) is deprecated due to known vulnerabilities.

• Most websites now use TLS, although many still refer to it as SSL.

SSL Certificates

• Websites must have an SSL certificate (technically a TLS certificate) to implement SSL/TLS encryption.

• Public key encryption is used for establishing secure communication.

• SSL certificates are issued by trusted Certificate Authorities (CAs).

Types of SSL Certificates

• Single-domain: Covers one domain (e.g., www.example.com).

• Wildcard: Covers one domain and all its subdomains (e.g., www.example.com, blog.example.com).

• Multi-domain: Covers multiple unrelated domains.

SSL Certificate Validation Levels

1. Domain Validation (DV):

   • Basic level; verifies control of the domain.

2. Organization Validation (OV):

   • More involved; CA directly contacts the organization.

3. Extended Validation (EV):

   • Highest level; requires a full background check of the organization.

Obtaining an SSL Certificate

• Cloudflare offers free SSL certificates with easy setup.

• Some websites may need additional setup for their origin servers.