What is SMS? How It works, why it’s insecure… and why we still need it

The killer app today for mobile phones is messaging, and there are countless messaging apps. Of course there’s Apple Messages, which is built into every iPhone, but there are plenty of third-party options, too. These include Meta’s apps WhatsApp and Facebook Messenger, as well as Telegram, Signal, Snapchat, and many others. (See our article comparing several popular secure messaging apps.)

Instant messaging on cell phones began with SMS, which stands for short message service (or short messaging service). Originally, an SMS text message could only contain basic characters, and had a tight limitation on message length. SMS has progressed a lot since its origin, and it’s still an important protocol today. Although it isn’t end-to-end encrypted, it’s not going away any time soon.

Let’s explore what SMS is, how it works, and why it’s still needed—even though it’s not secure.

Read the rest of the article on The Mac Security Blog.