A small Canadian software company has developed a security tool that identifies a computer user on the basis of his keyboard strokes.

Net Nanny Software International, of Vancouver in British Columbia, is better known for its eponymous Internet filtering technology. It posted on its Web site Bio Password, a security product based on a principle called ?keystroke dynamics?. The technology took around 20 years to develop, recounts president and chief executive Gordon Ross.

The technology was originally developed in the late 1970s, by the Stanford Research Institute. A company called International Bio access Systems (later renamed International Biometrics) extended the concept, but faltered in the early 1990s. Net Nanny now owns the defunct company?s patented algorithm, and is bringing it to market.

The technology registers the way a user types in a sequence of keystrokes ? such as a password ? measuring the time between strokes and how long the keys are pressed. These measurements are converted into an electronic signature, using a patented algorithm.

Though less secure than other biometric technology, such as finger or iris scanning, the patented keystroke dynamics technology has one important advantage, according to Ross: ?It?s very very cheap compared to other biometric systems, because you have no hardware to buy?.

Bio Password consists of software only, working with a standard keyboard. It combines easily with conventional passwords, providing an extra level of security against stolen or easily guessed passwords.

In the case of an eight character password, there is about a one in fifty chance that an imposter could match a registered user?s keystrokes closely enough to gain access, said Ross. This is assuming the imposter already knew the user?s password and was given an umlimited number of attempts.

The keystroke dynamics technology will also work with keypads, said Ross, opening the road to other possible applications such as ATM machines.

Net Nanny will launch its technology officially at Internet World in October. At that time, the company hopes to have the technology ready in the form of a COM object (Component Object Model) that can be used by OEM?s to add keystroke recognition to their applications.

Net Nanny also plans to integrate Bio Password with its Internet screening software, and will market it as a separate product to end users who wish to secure their files. The first commercial products to integrate Bio Password could reach the market by year?s end.

Bio Password will be licensed to OEM?s on a per-seat basis, with prices ranging ?from dollars to tens of dollars per seat?, said Ross.

He estimates the technology might earn the company hundreds of millions of dollars, suggesting this makes Net Nanny an attractive target for acquisition by a major company.