Following its very public encryption battle with the FBI, Apple has rehired software engineer and and security expert Jon Callas, reports Reuters. Callas, who has previously worked at Apple, is known for co-founding encrypted communications services Silent Circle, Blackphone, and PGP Corporation.

Apple's decision to rehire Callas comes amid rumors the company is working on improving the security of its iOS devices. Apple has said it will continually improve security to keep ahead of hackers, and its dispute with the FBI is said to have spurred the company begin work on implementing security measures "even it can't hack."



Earlier this year, Apple was ordered to assist the FBI in the unlocking of the iPhone 5c used by San Bernardino shooter Syed Farook, an order it fought because the FBI was asking for new software that would bypass iPhone passcode security measures. Apple insisted the software was "too dangerous to create," setting dangerous precedents that could lead to a weakening of overall device encryption. The FBI eventually dropped the case after finding an alternate method to breach the iPhone, but the fight over encryption is far from over.

According to Reuters, Callas supports Apple's position and is opposed to companies being compelled to break their own encryption by the government, but he believes law enforcement officials should be able to take advantage of software vulnerabilities, the method the FBI ultimately used to get into Farook's iPhone 5c.

Callas has said he is against companies being compelled by law enforcement to break into their own encrypted products. But he has also said he supports a compromise proposal under which law enforcement officials with a court order can take advantage of undisclosed software vulnerabilities to hack into tech systems, as long as they disclose the vulnerabilities afterwards so they can be patched.

An Apple spokesperson confirmed the hiring, but did not offer details on what Callas is working on. Callas was formerly employed at Apple in the 1990s and from 2009 to 2011, working on cryptographic security products for OS X and iOS.

Prior to its dispute with the FBI, Apple also acquired security company LegbaCore to improve the security of its software.