Shortly after Tim Cook took on his role as Apple's (AAPL 0.52%) CEO, he asserted that secrecy would still be a priority at the company. In fact, at the AllThingsD conference (now the Code Conference) two years ago, Cook told Walt Mossberg and Kara Swisher that he was going to take secrecy to a whole new level: "We're going to double down on secrecy on products. I'm serious."

Nevertheless, product leaks have persisted. Sure, the company has kept its policy to not speak about future product plans; the most detailed comment we've heard from Apple management is that it is working on products in new categories. But Apple simply can't keep a lid on its sprawling global supply chain.

Continued leaks have prompted Apple to fortify its efforts to stop leaks at suppliers. Will it work?

iPhone 6 rumors
For the most part, the Apple rumor mill is in consensus about the major details surrounding the form factor of Apple's iPhone 6. Leaks have suggested the company is working on 4.7-inch and 5.5-inch versions of the iPhone, with the 4.7-inch model to be released this fall and the larger iPhone to follow a few months later. MacRumors summarizes the rest of the major rumors, saying that the iPhone 6 will sport an improved A8 processor, a better camera, and new backlighting technology.

Just this week another leak provided the most convincing evidence that the iPhone 6 is, as rumors have suggested, taking on rounded corners like the iPod Touch, iPad Mini, and iPad Air. The leak of an alleged back cover of the 4.7-inch iPhone 6 fits the descriptions of the iPhone 6 that have surfaced in the Apple rumor mill. The photo comes from Macfixit Australia. The company says its source is a "contact in China."

These accurate descriptions of form factors are the foundation of realistic mock-ups and serve as a starting point for accessory makers and imitators.

MacRumors renderings by Ferry Passchier of the potential 4.7-inch and 5.7-inch sixth-generation iPhone lineup. Photo used with permission.

New efforts to stop leaks?
While its may be enjoyable for some Apple investors to follow product leaks, secrecy is undoubtedly the most shareholder-friendly route for Apple. As a product company that thrives by innovating in ways other electronics manufactures have not, keeping its designs secret as long as possible can give Apple strategic advantages over competitors, giving them less time to imitate designs.

But getting suppliers to tone down leaks isn't easy, as is clear by examining the detailed description of the iPhone 6 form factor making rounds in the Apple rumor mill. Even supplier alleged schematics of the phone's dimensions have leaked.

To help address continued leaks, Apple has reportedly hired about 200 security officers to try to catch those who are selling iPhone 6 accessories, according to a tweet on Friday from Sonny Dickson (via MacRumors), a frequent source of Apple hardware rumors.

Given the scale of Apple's business, such an expense makes sense -- that is, if it works. Can Apple really crack down on overseas product leaks? Or has Apple's supply chain simply hit a size that hardware leaks are basically inevitable?

Even if leaks accurate enough for accessory makers to begin early production are inevitable, investors should hope Apple continues its efforts in keeping future product plans as secret as possible -- backing off could encourage even more rampant leaks.