Why is there a lock symbol next to your text messages?

Have you noticed a lock symbol next to the text messages on your smartphone and wondered why? Here's what that symbol means ...
The Verge

Google is changing Chrome’s lock icon because nobody knows what it means

A new tune icon will replace it later this year to avoid misleading users about how ‘trustworthy’ websites are while browsing. A new tune icon will replace it later this year to avoid misleading users ...