Here's how you can keep your Twitter account secure — without paying $8 US a month

Twitter users were greeted early Saturday with an ultimatum from the social media app: Subscribe to the platform's new premium service or lose a popular account security feature.

A pop-up message warned users they will lose the ability to secure their accounts via text message two-factor authentication unless they pay $8 US a month to subscribe to Twitter Blue.

The message said that starting March 19, users who don't subscribe will be locked out of their accounts until they remove the security feature.

Here are some questions and answers about why Twitter made this change and alternative ways to secure your account:

Two-factor authentication adds a second layer of security to password-protected accounts by having users enter an auto-generated code to log in.

This extra step helps safeguard online accounts because in addition to the password, you need access to a separate app, device or phone number where you can receive the code.

Such codes can be generated by apps like Microsoft Authenticator or Google Authenticator. Or they can be sent to a user's smartphone via text message.

It's the text message-based two-factor authorization that Twitter is now restricting only to subscribers of Twitter Blue.

In a blog post on Wednesday, the San Francisco-based company acknowledged that the text message-based security method has been historically popular with its users, but it said the feature is being "used — and abused — by bad actors."

The company did not respond early Saturday to an email seeking more details on how the security method was being abused.

Elon Musk, who completed his $44-billion US takeover of Twitter last October, has been trying to find ways to maximize profits at the company.

One of those is Twitter Blue, which among other features allows anyone to pay for verification previously reserved for celebrities, journalists and other well-known people.

In its blog, Twitter encouraged users who are not going to subscribe to Twitter Blue to consider using alternative account security options, specifically an authentication app or security key.

These methods, which require you to have physical possession of the authentication method, are a good way to ensure your account is secure.