Apple’s iOS is the platform Asia-Pacific CIOs are most keen to deploy. Yet when it comes to security, it’s also the one they’re most anxious about.

That apparent disconnect shows up in IDC’s latest survey of regional IT decision-makers.

A hefty 43% said they most preferred iOS as the system to support their mobile apps and solutions; just chose 28% Android.

Yet when it comes to security iOS is the one they’re “most worried about.” Open-source, fragmented Android and its often-unpatched security holes comes in fourth.

The explanation probably lies in Symbian’s ranking as the OS that enterprise IT guys are least worried about. As IDC’s Claus Mortensen puts it, that’s because they aren’t planning to use it.

So the high nervousness about iOS most likely reflects its growing popularity as an enterprise platform.

From that perspective, the poll is a spot of good news for BlackBerry. It’s the fourth most preferred OS, chosen by 12% – just behind Microsoft/Windows Mobile.

But in the security anxiety rankings the BlackBerry 10 and BlackBerry 7 come in second and third respectively. Asian enterprises at least seem to have plans for BlackBerry.