For 15 years, Apple and the ad-tech industry have engaged in an escalating privacy battle, with Apple moving to prevent tracking by tech companies, and tech companies responding with new workarounds.

Apple’s latest move in the long-running fight came two weeks ago, when the company took action against so-called “CNAME cloaking” — a technique that allows ad-tech companies to masquerade as first parties.

Specifically, Apple updated the Mac operating system to recognize when ad-tech and analytics companies are using CNAME (short for canonical name) to cloak themselves, and to automatically cause cookies set by those companies to expire after one week.

The new setting is part of Apple’s “Intelligent Tracking Protection,” an initiative that aims to close a workaround to Safari’s default privacy settings — which have blocked third-party cookies since 2005.

Years ago, some ad-tech companies realized they could circumvent those settings by posing as first parties. Apple has been attempting to cut off that workaround since at least 2017, when the company first rolled out “Intelligent Tracking Protection.”

Intelligent Tracking Protection initially caused some first-party cookies to expire after 30 days, but that time frame was later shortened.

The feature led to a new round of escalation, with some analytics companies and advertisers developing a workaround by using a brand’s “canonical name” and then setting the type of cookie that Apple didn’t automatically expire.

The ad industry, which opposes Apple’s default anti-tracking settings, is criticizing the new canonical name policy.

“While they state they’re protecting the general privacy interests of the consumer, they don’t ask the consumers what they want,” Association of National Advertisers executive vice president Dan Jaffe tells MediaPost.

He notes in an ANA blog post that Apple also plans to restrict mobile tracking by preventing app developers from using the “identifier for advertising” — an alphanumeric string that enable tracking across apps — unless consumers consent on an app-by-app basis. The ad industry has loudly protested that move, arguing that companies will lose ad revenue if they need to ask consumers for opt-in consent to track them.

For now, Apple doesn’t appear to be backing down. The company said last month it plans to move forward with the mobile opt-in approach.

“What some companies call ‘personalized experiences’ are often veiled attempts to gather as much data as possible about individuals, build extensive profiles on them, and then monetize those profiles,” Apple said last month.

Meanwhile, Jaffe argues on the ANA blog that Apple’s new effort to restrict canonical-name cookies will “limit first parties from deriving important insights that enable them to better serve their customers.”

He adds: “This is not the first time Apple has taken unilateral action like this by imposing technical blockages on data flows without much warning and just on the heels of the holiday shopping season when online consumer experiences are more important than ever.”