According to a 139-page 10K form filed today, Apple is acquiring a 230-employee mobile security company called “AuthenTec” for $356 million. Apple’s $8 per-share offer is at a premium of 58 percent over AuthenTec’s Thursday close of $5.07.

On July 26, 2012, AuthenTec, entered into an Agreement and Plan of Merger with Apple, and Bryce Acquisition Corporation, a Delaware corporation and a wholly owned subsidiary of Parent, providing for the merger of Merger Sub into the Company, with the Company surviving the Merger as a wholly owned subsidiary of Parent. The Merger Agreement was unanimously approved by the Company’s Board of Directors.

The company owns 200 patents covering fingerprint sensors and sensor packaging, software, and end use. AuthenTec makes a variety of security tools, including a number of fingerprint scanners like the ones on the Motorola Atrix phone sold by AT&T, and it is responsible for the security behind the HBO Go app. The products range from secure networking and content and data protection to access control and fingerprint security on PCs and mobile.

Apple could use Authentec’s products in wallet applications, or just as a secure authentication mechanism for future products, which many businesses demand.

Just last week, AuthenTec entered an agreement with Samsung to implement secure VPNs for its Android hardware. (more on that at 9to5Google) Whoops.