TLS (Transport Layer Security) is the protocol that secures communication over the Internet.

It provides:

• Encryption
• Authentication
• Data integrity

TLS is used by HTTPS, secure email protocols, VPNs, and many other Internet services.

Originally, secure web communication used SSL (Secure Sockets Layer).

Over time, SSL was replaced by the more secure TLS protocol.

Today:

• SSL 2.0 — Obsolete
• SSL 3.0 — Obsolete
• TLS 1.0 — Deprecated
• TLS 1.1 — Deprecated
• TLS 1.2 — Widely used
• TLS 1.3 — Current recommendation

Although the protocol is now TLS, people still commonly say:

• SSL Certificate
• SSL Encryption

In most cases, they actually mean TLS.

Without TLS, information is sent as plain text.

For example:

Username

alice

Password

mypassword123

Anyone able to intercept the traffic may be able to read it.

With TLS:

Encrypted Data

Only the browser and the server can decrypt the communication.

TLS provides three essential security services.

Protects data from being read by others.

Verifies that the client is communicating with the intended server.

This is done using a digital certificate.

Ensures that transmitted data has not been modified during transmission.

Before encrypted communication begins, the client and server perform a TLS Handshake.

The handshake establishes:

• Supported TLS version
• Encryption algorithms
• Session keys
• Server identity

Simplified process:

Browser
      │
Client Hello
      ▼
Server

Certificate

Server Hello
      ▲
      │
Key Exchange

Secure Connection Established

After the handshake, all application data is encrypted.

Every HTTPS website presents a digital certificate.

A certificate typically contains:

• Domain name
• Public key
• Certificate Authority (CA)
• Expiration date
• Digital signature

Browsers verify the certificate before trusting the website.

Certificates are normally issued by trusted organizations called Certificate Authorities (CAs).

Examples include:

• Let's Encrypt
• DigiCert
• Sectigo
• GlobalSign

Browsers contain a list of trusted CAs.

A certificate may also be created by the server itself.

This is called a self-signed certificate.

Self-signed certificates provide encryption, but browsers cannot verify the server's identity.

As a result, browsers usually display a warning.

Modern websites should support:

TLS 1.2

or

TLS 1.3

Older versions are no longer considered secure.

Many browsers no longer allow connections using SSL or early TLS versions.

TLS is used by many Internet protocols.

Several Telenegar services examine TLS configuration.

Site Check can verify:

• HTTPS availability
• Supported TLS versions
• Certificate validity
• Certificate expiration
• Certificate issuer
• Hostname matching

These checks help identify common security issues before they affect website visitors.

Examples include:

• Expired certificate
• Self-signed certificate
• Wrong hostname
• Untrusted Certificate Authority
• Incomplete certificate chain

Browsers typically display security warnings when these problems occur.

• SSL and TLS are different technologies.
  • TLS is the modern successor to SSL.

• HTTPS means a website is trustworthy.
  • False. HTTPS only secures the communication.

• Encryption alone guarantees security.
  • False. Server configuration, software updates, and application security are also important.

• HTTP vs HTTPS
• Security Headers
• Site Check
• SPF Records
• DKIM Records

tls ssl https certificates encryption security