Twitter has bought Whisper Systems, a San Francisco-based startup that provides security software for Android smartphones and tablets. The price was not disclosed.
Whisper Systems announced the acquisition Monday on its website, saying that it would temporarily take down products and services in becoming a part of Twitter. The company didn't say for how long its products would be unavailable.
"Now that we're joining Twitter, we're looking forward to bringing our technology and our expertise into Twitter's products and services," the company said.
Whisper Systems distributes several beta products for phones running Google's Android operating system. The company's software provides full disk encryption, network security tools, a firewall and encrypted text messaging. For services, the company provided data backup and encrypted voice calling.
San Francisco-based Twitter was unavailable for immediate comment.
Twitter has provided mobile apps to subscribers for some time. The microblogging site's iPhone app, updated in March, is the third most popular vehicle for accessing Twitter, after Twitter.com and mobile.twitter.com, the company says.
Twitter has had its share of security problems. In September, hackers tapped into the Twitter account of NBC News and posted a message saying terrorist had launched an attack at Ground Zero in New York. The message was timed to coincide with the 10-year anniversary of the September 11th World Trade Center attacks.