Abstract: Magnetic stripe documents are identified and authenticated on the basis of repeatable magnetic characteristics of a stripe recorded with digital data and waveform characteristics of the sensed digital data. Stripes are sensed to provide an analog signal, only the portion storing leading zeros being used. Cyclically, the leading-zero portion is sampled and digitized to provide a target number of samples using a frequency locked loop. The target number of samples is then reduced by a selection process that attains a predetermined number of digital samples from central locations in magnetized portions of the record specifically, spaces between data transitions. Selected groups, each of a predetermined number of digital samples, are then combined to provide magnetic characteristic data. Such data is then combined with waveform data (range) to provide an identification word. Documents are verified by correlating reference and sensed identification words.

Abstract: A system for verifying the authenticity of data contained in a magnetic medium using the remanent noise characteristics of the magnetic medium. In one embodiment, the invention includes a sensing unit configured to generate a signal indicative of the magnetic field of the magnetic medium, an analog-to-digital converter (ADC) in communication with the sensing unit and configured to digitize the analog signal, a filter in communication with the ADC configured to enhance the component of the signal associated with the remanent noise characteristic, a data extraction unit, in communication with the ADC and the filter configured to measure at least bit duration and peak location and an authentication extraction unit, in communication with the filter and the data extraction unit configured to extract a set of scaled samples from the output of the filter representative of the remanent noise characteristic.