While most hackers have had only positive intentions, such as wanting to install applications or unlock the phone for other carriers, Runald points out that the common technique of "jailbreaking" an iPhone is also what could allow serious damage. "What they're doing is they're breaking out of the iPhone's secure mode, [which] is that you're not allowed to venture outside of the UI." Once this stage is reached, Runald says, "you're out of the shield, you can do anything." The decision to open up the iPhone to third-party applications in February may have both negative and positive ramifications, Runald observes. Distributing the SDK could in theory make it simpler to develop malware, but at the same time, it could make it possible to install security software, countering the threat. The principal advantage the iPhone will retain is that because it uses a stripped-down version of Mac OS X, there are still fewer avenues of attack than on a desktop system.