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.