The U.S. Department of Defense has authorized its Network Information Center to sign the .mil zone with DNSSEC, it was announced. The move is a major step forward in the U.S. government’s efforts to deploy DNSSEC across its domains.

Limited to use by the U.S. military, the .mil top-level domain will be signed over a three-month period, starting with an unvalidatable key and progressing to publication of the .mil key to allow validation across the Internet. The tentative timeline calls for the zone to be signed by December 12, 2011.

The .mil is a sponsored TLD and was one of the first top-level domains, created in January 1985.  The U.S. is the only country with a top-level domain for its military.