RUSTON, La. (AP) -- The way you type is as unique as your eye color or speech patterns and can be used instead of a password to protect your computer, researchers at Louisiana Tech and Penn State say.

Their discovery will bring Louisiana Tech its first direct royalty income, university president Daniel D. Reneau said in signing a joint licensing agreement with BioPassword Inc. of Issaquah, Wash.

Vir Phoha, associate professor of computer science, and former graduate student Sunil Babu worked with others at The Pennsylvania State University to create the technology over five years of research.

"We look at the time between keystrokes, and the time it takes to press a key," Phoha said. A percentage of the royalties will be plowed back into the research program, Phoha added.

BioPassword holds the rights to several patents on such software, according to its Web site.

The company says its programs should not be used as the only security system but in addition to passwords and other measures.