Apple is offering cyber security researchers up to $1 million to detect flaws in iPhones.

The company previously offered rewards only to invited researchers who tried to find flaws in its phones and cloud backups.

At the annual Black Hat security conference in Las Vegas on Thursday, the company said it would open the process to all researchers, add Mac software and other targets, and offer a range of rewards, called “bounties,” for the most significant findings.

The $1 million prize would apply only to remote access to the iPhone kernel without any action from the phone’s user. Apple’s previous highest bounty was $200,000 for friendly reports of bugs that can then be fixed with software updates and not leave them exposed to criminals or spies.

Government contractors and brokers have paid as much as $2 million for the most effective hacking techniques to obtain information from iPhones.