Missing laptops and disappearing disk drives made headlines last year. Yet little has been written about the damage that results from unauthorized access to network traffic through an unsecured notebook or personal digital assistant by an unauthenticated user. Laptop theft is a drop in the bucket compared with the danger of a stranger gaining network server privileges through remote access.

Without trust in the security methods used to protect network data, remote dial-up access faces huge challenges. These hurdles can be overcome by designing biometric devices into the keyboards of desktop PCs, the palm rests of notebook computers-and even into PDAs and cellular telephones. But it will take smaller, more accurate and convenient solutions to overcome the problems arresting the success of remote access and mobile commerce.

Most companies use virtual private networks or public-key infrastructure solutions, but both depend on the weak security link of passwords or PINs. Passwords are easily guessed or stolen and an unattended laptop is vulnerable to unauthorized use when left alone by a logged-in user.

Biometrics technologies-using identifiers that are an undeniable part of a person-are the easiest and most secure answer to overcoming the problems of remote access. Among the solutions available, silicon fingerprint sensors offer portable-device designers the most flexibility. For fingerprint-sensing technology to benefit mobile commerce and remote access, however, the chips need to meet the specific size, weight and power needs of mobile computing and communications gear, as well as the stringent accuracy requirements for authentication.

Silicon sensor chips-which are 1.4 millimeters thick and have dimensions of 24 x 24 mm-give designers an opportunity to offer fingerprint authentication without sacrificing real estate. The size of these chips, which use thousands of capacitors to digitize a fingerprint, will continue to shrink as authentication becomes a necessity in transactions and data access using PDAs and cell phones.

Using silicon chips for fingerprint authentication is one of the least expensive biometrics technologies to integrate. Fingerprint chip prices will soon drop below $10 each.

The most compelling argument in favor of designing such chips into portable devices is convenience. Users typically say it's a relief to be rid of passwords and PINs. Lightly pressing your index fingertip on a postage-stamp-size sensor is simple and generates the trust needed to conduct business or exchange sensitive information over the Internet, intranets or networks without fear or fraud.

Michael R. D'Amour is president and chief executive officer of Veridicom Inc. (Santa Clara, Calif.).