Apple's privacy chief regretted creating its infamous ad-tracking tool after dev...

• Apple's privacy chief regretted building the tech giant's IDFA tracking tool, per The Information.

• Erik Neuenschwander and his team created the identifiers to track users across devices.

• The identifiers became the industry norm, which sources told the publication troubled him.

Apple's head of privacy regretted creating the company's tool that lets them track users and target them with ads, sources told The Information in a new report.

Erik Neuenschwander and his team created IDFA, which stands for the identifier for advertisers, after he become chief of Apple's product security team in 2011, per the report. He has been with the company since 2007, according to his LinkedIn profile.

Neuenschwander's group designed the software-based IDFA to replace hardware-based identification codes, since the latter couldn't allow the tracking of users across devices. However, codes baked into the operating system could. The team also built a feature that let people switch off the tracking identifier, but the majority of users did not use it.

These identifiers have since become the norm in the advertising industry, allowing third parties access to user data to target them with ads. Google eventually created a similar tool, for example.

And as The Information notes, the current standards weren't what Neuenschwander and his team originally intended.

Developers began finding loopholes in the identifier's rules, such as continuing to track users even if they had turned off IDFA. Neuenschwander's team added new guardrails in 2014 and 2016 to make it harder for developers to circumvent users' tracking wishes, according to The Information, but developers found ways around those, too.

It was after Neuenschwander and his team rolled out new rules in 2016 that he started telling colleagues he regretted building IDFA, people who have worked with him told The Information. Software identifiers becoming the industry standard especially began bothering him, per the report.