NEW CANAAN, Conn. — Demands for IT security professionals are approaching levels not seen since shortly after Sept. 11, 2001, according to Foote Partners, an IT workforce research firm and consultancy that tracks certification and compensation data from nearly 1,900 employers and 33,800 employees across the United States and Canada. Key measures such as IT security certifications as a percentage of base salary have spiked upward in the past few months, the consultancy says, while other certifications fell or stayed the same in value. "When we see unusual upward trending for specific jobs and skills, this most often indicates specialized skill demand that is rising faster than supply," says David Foote, the firm's CEO and chief research officer.