In what may be its first-ever security-related acquisition, Twitter has purchased Whisper Systems, a year-old start-up that provides Android defenses.

Whisper Systems, which offers security and management solutions, such as encryption, to enable mobile devices to become enterprise ready, was co-founded by well-known researcher Moxie Marlinspike. Terms of the deal, announced Monday, were not disclosed.

“Now that we have been acquired by Twitter, we’re looking forward to integrating our technology and our expertise into Twitter’s products and services,” read an announcement on Whisper’s blog.

It is unclear how the microblogging service will implement Whisper’s solutions into its product line. Prior to the acquisition, all of Whisper’s source code was available for review.

“As part of our fast-growing engineering team, they will be bringing their technology and security expertise to Twitter’s products and services,” Twitter said in a statement, sent to SCMagazineUS.com on Monday evening EST.

The blog post said Whisper was launched because its creators were concerned that mobile devices would suffer the same threat-filled fate as the traditional desktop environment.

“We ended up tackling the full stack — all the way from application-level solutions at the top of the stack, down through a hardened version of Android, to kernel modifications at the bottom of the stack,” the blog entry said. “Along the way, we learned a lot, and developed products that we’re proud of.”

As a result of the deal, however, Whisper must take its product line offline. First to go is RedPhone, its voice encryption product for the Android. Flashback, which stores encrypted backups, is expected to be disconnected next month.