Twitter has open sourced TextSecure — an Android text-messaging client the company acquired earlier last month with the purchase Whisper Systems, an outfit founded by well-known security guru Moxie Marlinspike — and in the coming months, it plans to release the rest of Whisper’s security-minded software.

On Tuesday, Twitter announced that the TextSecure code is already available on GitHib and that more is on the way. “Before we fully release Whisper Systems’ code to the public in the coming months, we need to make sure it meets legal requirements and is consumable by the open source community,” the company said in a blog post. “The plan is to open source the code in an iterative fashion, starting today with TextSecure.”

Marlinspike and roboticist Stuart Anderson founded Whisper Systems two years ago, aiming to provide “enterprise-grade” security for phones and tablets running Google’s Android operating system. Both are now Twitter employees — Wired spotted Marlinspike at the legendary San Francisco watering hole Hotel Utah with what appeared to be his new employers — but it’s unclear what they’ll be doing for the company. Twitter declined to provide additional details on its acquisition.

With today’s announcement, however, Twitter seemed to confirm the obvious — that it’s not getting into the software business.

Alongside TextSecure, Whisper developed tools such as WhisperCore, a device and data encryption tool, and WhisperMonitor, a firewall that vets outgoing data and connections.

When Twitter announced the acquisition of Whisper System, security expert Chris Soghosian bemoaned the move — at least on one level — because he felt that it would undermine Whisper’s efforts to aid the Arab Spring uprising. Immediately after the acquisition, Twitter shut down Whisper’s RedPhone, an encrypted calling service meant to help Arab protesters organize demonstrations. Soghosian worried this would leave many Egyptians without a safe way to communicate during their elections last month.

“[RedPhone] is targeted just for Egypt, but sets the stage for worldwide support,” Marlinespike told Wired in February. “Hopefully with stuff happening in Egypt it kind of steps things up [regarding distribution to other countries].”

Marlinspike did not immediately respond to a request for comment.

[Photo: Anthony Gattine/Flickr]