Information Embedding Method for Home Printing of Certifications

In this paper, we describe our dot-pattern code, which can embed information onto the paper. Its main features are 1) no need to reserve a special room for the code, 2) obscure and unnoticeable, 3) comparatively large information capacity, 4) the absolute coordinates in the paper is measurable. We describe how to embed and detect the information onto / from the paper, and we estimate it by examination. From the examination, we found that our dot-pattern code is applicable to various kinds of papers, printers including ink-jet and scanners. We also found that even when the density of the black dot is greater than 6 %, over 8,000 bits could be safely embedded with error rate less than 10^-6 . We also found that the embedded information could be detected correctly after the paper had been damaged.