Patent ID: 7706594

Claim:
A text document authentication method, comprising: creating a document, where said document has text thereon; creating at least a portion of the text with a combination of marking materials, including a first, visually perceptible marking material and a second, visually perceptible marking material, wherein the second visually perceptible marking material further includes a detectable, yet not visually perceptible, characteristic so as to be distinguishable from the first marking material with an aid, and where placement of the second visually perceptible marking material is indistinguishable from the first visually perceptible marking material to the unaided eye, yet is in a predefined pattern signifying the authenticity of the document containing such a pattern; and reading the second marking material pattern, with the aid, so as to verify the authenticity of the document, said reading step being sensitive to the presence of the detectable characteristic of the second marking material so as to identify the predefined pattern.