Embedded variable curved spiral patterns

A method of verifying documents, the method comprising:

• obtaining an image of a document;
• identifying, within the image, a spiral pattern applied to a region of the document, wherein the spiral pattern comprises an elliptical spiral segmented into a plurality of arc segments, wherein the plurality of arc segments are portions of a continuous line converging on a center position of the spiral pattern;
• determining, from the spiral pattern, spiral data that indicates characteristics of the spiral pattern;
• determining, based on the spiral pattern and the spiral data, secure information of an individual associated with the document;
• and
• verifying the document based on the secure information.

A computer-implemented method, comprising:

• obtaining card type data and/or user data to be embedded in a document;
• determining one or more line features to be implemented in the document;
• determining a wave function associated with a graphic to be implemented in the document;
• and
• controlling by control signals an embedding device to embed user data in the document based on the one or more line features and the wave function, wherein controlling by control signals comprises applying the wave function to a control movement of a laser while engraving the document, wherein the control signals comprise coordinate data for identifying locations of graphics and line segments with reference to an XY plane of the document.