Anonymizer, the pioneering online privacy company, was acquired Thursday by a highly specialized national-security technology provider. Anonymizer began in 1995 as a provider of technology to help consumers, and later enterprises, protect their identities online. The company has a variety of products now that enable users to avoid spam, surf Web sites anonymously and protect their email addresses. It is probably best known for its Anonymous Surfing product, which redirects users’ Web traffic through a proxy, hiding their actual IP addresses. But it also offers products that provide users with disposable email addresses and offerings for enterprises that enable executives to check out competitors’ sites anonymously.

The company acquiring Anonymizer, Abraxas, is a provider of technology and risk management services to the national security community and was founded by Richard H. Helms, a former CIA officer (no relation to Richard M. Helms, former director of CIA). The two companies, both based in San Diego, already share some similarities. Lance Cottrell, the founder and chief scientist at Anonymizer, is also chief scientist at Abraxas. Abraxas’ board of advisers includes former DHS secretary Tom Ridge, and Alan Wade, the former CIO of CIA.