Patent ID: 7796777

Claim:
A digital watermarking system comprising: a storing unit for storing text information, the text information comprising one or more dot matrix files; a text obtaining module for obtaining a dot matrix file to be watermarked from the storing unit, wherein the dot matrix file comprises a plurality of dot matrixes, and each of the dot matrixes has a matrix margin, comprises a plurality of pixels; and each of the dot matrixes is defined to be of one of at least two types, the at least two types comprise an alphanumeric character type and a punctuation type; a dot matrix determining module, for earmarking a dot matrix to be adjusted if a length of a bit sequence is not equal to zero, wherein the bit sequence comprises an instruction for watermarking the text information; an encrypting module, for adjusting the matrix margin of the earmarked dot matrix according to a bit value of one bit of the bit sequence; and a storing module, for storing watermarked text information in the storing unit.