Counterfeit prevention for optical media

A method for issuing authenticity information to an optical medium, wherein the method is carried out by a computer system, the method comprising:

• generating on the optical medium a fingerprint including at least one probabilistic feature, wherein a probabilistic feature is a physical feature having both a chance to be read indeterminately as a first value and a chance to be read indeterminately as a second value;
• calculating an optical-DNA signature-at-issuance, including reading the fingerprint a predetermined number of times and assigning to each probabilistic feature a value corresponding to a number of times each probabilistic feature is interpreted as the first value;
• and
• establishing a threshold that represents a boundary between a true positive from a true negative, and wherein a true positive is indicated by a vector-of-differences between the optical-DNA signature-at-issuance and an optical-DNA signature-at-verification of the optical medium, and wherein a true negative is indicated by a vector-of-differences between the optical-DNA signature-at-issuance and an optical-DNA signature-at-verification of a different optical medium.

One or more computer-readable storage devices comprising one or more instructions to verify authenticity information on an optical medium, wherein the one or more instructions, when executed, direct one or more processors to perform actions comprising:

• receiving the optical medium including a fingerprint having at least one probabilistic feature, wherein a probabilistic feature is a physical feature having both a chance to be read indeterminately as a first value and a chance to be read indeterminately as a second value;
• receiving an optical-DNA signature-at-issuance, including for each probabilistic feature a value corresponding to a number of times an issuance system had read each probabilistic feature as having the first value, wherein the issuance system had read each probabilistic feature plural times;
• calculating an optical-DNA signature-at-verification by reading each probabilistic feature plural times and assigning to each probabilistic feature a value corresponding to a number of times a verification system read each probabilistic feature as having the first value;
• and
• calculating a vector-of-differences between the optical-DNA signature-at-issuance and the optical-DNA signature-at-verification, wherein the vector-of-differences includes a maximum distance metric between the optical-DNA signature-at-issuance and the optical-DNA signature-at-verification, and wherein the vector-of-differences indicates a true positive if the maximum distance metric is less than a threshold, and wherein the vector-of-differences indicates a true negative if the maximum distance metric is greater than the threshold.