This paper explores whether features of structured writing can serve to discriminate users of handheld devices such as Palm PDAs. Biometric authentication would obviate the need to remember a password or to keep it secret, requiring only that a user’s manner of writing confirm his or her identity. Presumably, a user’s dynamic and invisible writing style would be difficult for an imposter to imitate. We show how handwritten, multi-character strings can serve as personalized, non-secret passwords. A prototype system employing support vector machine classifiers was built to discriminate 52 users in a closed-world scenario. On high-quality data, strings as short as four letters achieved a false-match rate of 0.04%, at a corresponding false non-match rate of 0.64%. Strings of at least 8 to 16 letters in length delivered perfect results—a 0% equal-error rate. Very similar results were obtained upon decreasing the data quality or upon increasing the data quantity.
Rachel R. M. Roberts, Roy A. Maxion, Kevin S. Kill