There are several laudable reasons for wanting to jailbreak your iPhone or iPod touch. An opportunity to choose your own mobile provider, customise your phone and settings and add applications that aren't available from Apple's own store. Another reason, much less laudable, is to download applications that are cracked and you haven't paid for. Games particularly can be found online without much effort, indeed several come up in very innocent searches for reviews and iPhone developers websites. Unlike global companies with money in the bank, many iPhone developers are small one man or woman businesses hoping to make a living from something creative in their spare time.

Ben Gotow of Gotow.net, while still an undergraduate in the School of Engineering at Vanderbilt University, has created Layers for iPhone and iPod touch. The application has received rave reviews and is billed as the most advanced natural media painting application on the platform. While Layers offers a useful set of painting tools and layers within an intuitive interface, it’s also attracted unwanted attention from pirates cracking the application and putting it online. Macworld spoke with Ben to discover the scale of the problem.

Q. People might assume it is just the 'big boys' who suffer from piracy, but that's not the case?

I'd imagine piracy rates are pretty high across the board. There are websites that make it easy to find and download pirated apps, so getting cracked copies of small-time apps isn't a big issue. One of the pirate sites, Appulo.us, allows users to browse more than 9300 cracked apps and some sites have torrents of thousands.

I think there's probably a strong correlation between price and piracy. Layers is on the upper end of the price scale at $5/£2.99 and I'd imagine that contributes a lot to the high piracy rates I've seen. I'd be interested in gathering data and seeing how others have fared, though.

Q. How did you discover how many people were using your app on jailbroken iPhone and iPods?

I get Google Alerts when new search results appear for "Layers for iPhone," and one morning I noticed that several people had posted torrents of cracked copies of the app. I did some investigation and found an app for jailbroken devices that would automatically crack apps downloaded from the App Store. The cracking process looked very straightforward, and the app provided a nice interface for doing everything: no manual hacking or terminal use required! A few days later, I spoke to a reporter from ARS Technica about Layers and he introduced me to Appulous.

I found a cracked version of Layers in the Appulous database, and the app's page showed more than 9,000 downloads. I couldn't believe it! AdMob does jailbreaking analytics as part of their statistics services, and I decided to add something similar to Layers. If the app determines that your iPhone is jailbroken or that the app is cracked, it phones home to one of my servers. The submitted information is completely anonymous but it lets me to get a general picture of how many pirated copies are in use.

This month, pirated downloads have outpaced paid downloads 3:1 and more than 800 pirated copies have phoned home in the last week.

Q. And how did you feel?

I was pretty shocked. I figured piracy would be a small issue since the jailbreaking community is estimated to be a few million phones at most. It's somewhat flattering to know that someone took the time to crack the app, but I understand why large software companies go to such great lengths to protect expensive products. I debated a couple of ways of locking down cracked copies of the app, but in the end I decided to make the process of phoning home unobtrusive and give pirated users full access to the app.

Q. Do you think those who haven't paid is lost revenue or are they unlikely to pay anyway?

I think it's unlikely that pirates would have bought the app. A few developers have correlated downloads of "lite" apps to their "pro" counterparts, and it seems like very few people upgrade from free to paid applications. I imagine the same thing would be true for app piracy. While I'm sure I've lost some revenue, I'd estimate it's less than 10 per cent of the $21,000 the pirated copies are worth.

Q. In practical terms how does piracy effect your business and future applications?

At the end of the day, piracy does affect the bottom line. Building "Layers" was a major undertaking, and it's difficult to justify complex apps when piracy rates are so high. The market for painting tools on the iPhone is pretty small, and every sale helps justify the cost of development. I really enjoy writing iPhone apps and I've considered doing it full-time after graduation this spring. Cutting down piracy would probably boost sales and would help justify a career move in that direction.

Layers: Pirated vs. legitimate downloads in the last 30 days.

Q. Apple must be aware of the problem, do you think they do enough to limit iPhone piracy?

I don't think Apple does enough to limit app piracy. Until recently, the iPhone marketplace was heavily biased toward 99¢ apps, and it made it difficult to justify the development of a complex application. While they've corrected the store by adding a list of "Top Grossing" apps, piracy is still making it difficult for developers to write expensive apps. For every copy of Layers sold through the store, three more are downloaded illegally. That's pretty bad for a $5/£2.99 app, and I imagine apps like TomTom GPS ($99/£59.99) are even more severely undercut by piracy.

Q. And as a developer, once the application is cracked, is there much you can do to reverse the process?

Not really. Once the application has been cracked and posted on the internet, it's difficult to reverse the process. You can write logic into the app so that it does things when it detects it’s been pirated; since jailbreaking the iPhone disables sandboxing in the kernel, you could feasibly do whatever you wanted to the person’s phone. Every pirated copy helps advertise the app a bit, though - and after a point, there's only so much you can do. A determined hacker could edit the executable code manually and disable even the best piracy checks within the app.

Q. Do you think if developers could offer limited trial applications that say ran for a month, would that help prevent piracy?

Yes, absolutely. I'd also like to see Apple implement a "purchase confirmation" system similar to the one used for "In-App Purchase." It'd be great if your app could securely contact an Apple server and ask "Can I see a receipt for my purchase?" It'd be an easy way of validating the app and preventing pirated users from getting a free ride. Traditional software validates the serial number you provide, and I don't see why iPhone apps should be any different. The infrastructure is there already for "In-App Purchase" in iPhone OS 3.0, but I'm sure Apple is hesitant to draw attention to the piracy issue.

Q. Layers has been a critical hit with both reviewers and users, what future plans do you have for iPhone applications etc?

I'm working on a few features for Layers that I'm pretty excited about. I've written a smudge tool and I'll be adding it to the app in the next few weeks - since layered drawing seems to be catching on! - and offset brushes might come a little later this fall. I don't have any plans for a new app yet, but I've been working with Dr. Jules White here at Vanderbilt to develop an augmented reality library for the iPhone. If all goes well, I may try to write a location-aware app this winter.

(Available from the Apple iTunes App Store, Layers costs £2.99 and requires the iPhone 3.0 Software Update. Macworld's review of Layers is here.)