The balancing act

Technology has come to play a key role in access control, with ID-based access cards now widespread and viewed as the preferred approach. The passage of time has seen a progression from a simple magnetic stripe to complex chip cards, designed to offer increased security and ease of use. While systems have become more sophisticated, so too have the methods criminals use to decipher the codes and it is this race to stay ahead that is driving a rapid evolution in the security industry.

In typical manufacturing environments, investing in biometric applications offers an effective method of monitoring access control. But when access involves actual bodily contact for user authentification, such as in a cleanroom environment, the situation is harder to achieve without compromising product safety.

Sign Assured is one company that has been able to develop a solution that ensures that people working in a cleanroom environment can maintain high levels of security without compromising hygiene levels. The SignHear device allows staff who are obliged by their company to wear protective clothing to adopt a secure and convenient biometric system.

The system is based on technology that emerged in the 1980s when research scientists at Rolls-Royce started looking into methods of detecting structural faults in turbine blades. It has since been adapted for use in other industries, thanks to the expertise of specialist company Datalink Electronics.

The SignHear technology is based on the emission of sound pulses that fire into the object. Depending on the different types of cracks present, these pulses reflect back a host of acoustic signals. By comparing the reflected signals with known patterns, it is possible to determine the level of damage suffered. During the development of this method, one of the researchers, noting his colleague writing on a piece of paper, joked about how he was ‘creating acoustic emissions with his pen on the paper’. This comment sparked the eventual development of a system for verifying handwritten signatures using sound.

The technology picks up the sound the signature generates when a pen drags across its signing surface. The acoustic signals collected are a combination of important information contained within the signature. Since the pen uses the sound of the signature, the signing surface does not need to be a highly sensitive electronic membrane, which is a common feature of other signature verification systems.

Biometric signing
Signing is biometrically unique to us all because the writing of a signature is a mixture of an individual’s personality and the subconscious movements of muscles associated in holding a pen. Replicating the image is easy but replicating how it is done is much more difficult. It is this unseen behaviour of signing which SignHear captures and uses to verify its users. The combination of movements across a surface creates a set of sounds that is uniquely identifiable to the user, rendering replication from an image almost impossible.

Unlike many of the other physical biometrics such as fingerprints, hand-scanners and facial recognition that will verify the user despite their wishes, authentication of the SignHear technology cannot proceed without the voluntary consent of the user.

The sound produced by the pressure and speed of the signature is stored as a template on the device. This is subsequently used by the system to recognise the user on their return. If the device fell into the wrong hands and the templates were compromised, the user’s signature would remain safe. The templates are a record of the sound and this cannot be converted into a visual image. In addition, no two signatures, in terms of the sounds generated, are identical. While the device is able to accommodate these changes, it also provides natural encryption because if it sees two identical signatures, it blocks access.

The device means staff working in cleanroom environments can achieve high security in their workplace without compromising product safety, as users are able to hold the signing stylus/pen through gloves. Installation is simple and can be used in conjunction with other card technology-based systems or can replace them. Early indications are very encouraging and the results from a Beta site situated within a company in the Midlands have produced positive results. Two laboratory facilities in Manchester and Hampshire are seeking to adopt this new technology to enhance their existing security system.