Since Google said last year that it had devised a custom chip for accelerating machine learning, there has been much chatter about the rise of specialized hardware for complex tasks like image recognition.

But the search engine company recently hinted that machine learning was not the only task that required custom silicon. In a recent overview of its data center security, Google said that it had devised “a hardware security chip” to verify the identity of devices inside its servers.

The chip is “currently being deployed on both servers and peripherals,” the company said. “These chips allow us to securely identify and authenticate legitimate Google devices at the hardware level.” It is unclear when the company first installed the chips, but they appear to be its latest strategy for storing security code.

Google added that with “each new generation of hardware, we strive to continually improve security: for example, depending on the generation of server design, we root the trust of the boot chain in either a lockable firmware chip, a microcontroller running Google-written security code, or the above mentioned Google-designed security chip.”

The existence of the security chip was first reported Monday by The Register, an information technology news website.

The security chip is another sign that internet companies are willing to invest in chips that fit the unique demands of their server workloads. Microsoft, for instance, using custom FPGAs in its cloud servers that can be programmed and optimized for an array of difficult chores. Facebook, too, has devised its own type of graphics processors.

Google said that its chip creates a hardware root of trust, which entails locking a cryptographic signature in a special part of the chip where it cannot be altered. Google said that its machines validate that code during each boot and update. The company did not immediately respond to a request for more information.

Google has been building custom servers for years, but until recently has been content to buy chips from companies like Intel. Google has quietly changed its tune, hiring chip designers and buying start-ups with tools for programming multicore processors. In 2010, it purchased a secretive company founded by former employees of P.A. Semi, which Apple bought in 2008 to design iPhone chips.

Google's semiconductor plans became clearer last year. The first sign came in February, when it became known that the company had built a processor for network interface cards that connect servers to a larger network. Its first big chip announcement followed several months later in May at Google's I/O developer conference.

Sundar Pichai, Google’s chief executive, revealed an accelerator chip for machine learning programs, which is said to be three processor generations ahead of other devices. The chip, he said, has been used to enhance Google’s search engine and an artificial intelligence program that has mastered one of the most devilishly complex board games in history, Go.