Apple will release a true software development kit (SDK) for the iPhone next February, promised company CEO Steve Jobs today.

Jobs penned an open letter which has been made available on Apple's website. In this letter he confirms the company wants to nurture a vital development community around iPhone, but also wants to ensure sufficient protection is in place to prevent malware and viruses sneaking into the advanced handheld.

"We are excited about creating a vibrant third party developer community around the iPhone and enabling hundreds of new applications for our users," writes Jobs.

"With our revolutionary multi-touch interface, powerful hardware and advanced software architecture, we believe we have created the best mobile platform ever for developers," he added.

The secretive Apple boss didn't promise too much, but his note suggests Apple will apply some protective measures to ensure against malware authors.

"It will take until February to release an SDK because we’re trying to do two diametrically opposed things at once - provide an advanced and open platform to developers while at the same time protect iPhone users from viruses, malware, privacy attacks," Jobs explains.

Apple continues to explain that viruses and malware are a growing threat to mobile devices, observing that the high profile of the device is bound to make iPhone a target for such attacks.

He points to Nokia's digital watermarking protection for its devices, a scenario in which applications cannot be installed into such devices unless a digital signature which tracks back to a known developer is in place. "We believe it is a step in the right direction," he states.

"We are working on an advanced system which will offer developers broad access to natively program the iPhone’s amazing software platform while at the same time protecting users from malicious programs," Jobs ends.

Read his comment in full here.