SSL (Secure Sockets Layer)

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.

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