Authenticating multi-layered objects using encoded signals

A method for creating a tamper-evident feature for product authentication, the method comprising:

• generating a payload comprising encoded product information;
• applying robustness encoding to the payload to produce a set of encoded message components;
• mapping the encoded message components to locations on different product parts, comprising at least mapping a first subset of encoded message components to a first product component and mapping a second subset of encoded message components to a second product component different from said first product component;
• adapting robustness of the encoded message components differently across the different product parts by selectively modifying robustness characteristics of the encoded message components based on respective locations, wherein adapting robustness comprises varying levels of robustness encoding applied to each subset of encoded message components;
• assessing robustness tolerances of the encoded message components by determining message detection scores;
• and
• iteratively adjusting the robustness of the encoded message components until optimal tolerances are achieved.

A tamper-evident product comprising:

• a first product component and a second product component different from said first product component;
• a payload comprising encoded product information;
• and
• encoded message components produced by applying robustness encoding to the payload,
• wherein the encoded message components are mapped to locations on the first product component and the second product component, comprising at least a first subset of encoded message components mapped to the first product component and a second subset of encoded message components mapped to the second product component;
• wherein robustness of the encoded message components is adapted differently across the first product component and the second product component by selectively modifying robustness characteristics of the encoded message components based on respective locations, and
• wherein successful reading of the encoded product information requires contemporaneous scanning of all encoded message components in their original applied positions, such that any tampering involving separation, removal, or repositioning of any product component bearing encoded message components renders the encoded product information unreadable.

A method for authenticating a product having tamper-evident features, the product comprising a first product component and a second product component different from the first product component, the method comprising:

• scanning encoded message components from the first product component and the second product component, wherein a first subset of encoded message components is mapped to the first product component and a second subset of encoded message components is mapped to the second product component;
• contemporaneously reading the encoded message components in their original applied positions;
• applying error correction decoding to the encoded message components to reconstruct encoded product information from robustness encoding that was applied to a payload comprising the encoded product information;
• determining message detection scores to assess robustness tolerances of the encoded message components;
• and
• generating an authentication result based on successful reading of the encoded product information, wherein any tampering involving separation, removal, or repositioning of any product component bearing encoded message components renders the encoded product information unreadable.