Hifn was a semiconductor manufacturer founded in 1996 as a corporate spin-off from Stac Electronics. Its name was originally styled as Hi/fn, and located in Carlsbad, California. The company was later headquartered in Los Gatos, California, and had offices in North America, Europe and Asia. It designed and sold security processors.

It was acquired by Exar in 2009.

Hifn was founded in 1996 as a spin-out of the semiconductor company Stac, Inc. It held its initial public offering in December 1998. The company's stock was traded on the NASDAQ under the symbol HIFN.

Hifn was the first company to offer a processor with integrated encryption and compression in 1998, and followed this in 1999 with the fastest security processor for VPNs.

In 2000, Hifn announced an Intelligent Packet Processor - a security co-processor capable of not just performing raw algorithm processing, but of modifying the complete packet, allowing their processors to transform an IP packet into an IPSec packet in a single pass in the security processor with only the policy and IPSec stack being required on the host CPU. They announced a security processor featuring the Advanced Encryption Standard (AES) algorithm in 2001.

In 2004 they followed on from their packet processor with an IPSec protocol processor capable of performing IPSec and Internet Key Exchange processing with no CPU intervention. They also adapted this processor for the storage area network market, for applications such as iSCSI. A secondary offering was priced on April 12, 2004.