Abstract
Copyright protection of digital images received increasing attention in the last decade due to massive digital artwork distribution via internet, so digital watermarking was a potential solution to such problem. Invisible watermarking scheme has been applied in frequency domain, to embed a logo image inside a large original image. The bits of the logo image are embedded in random color components of the original image, as well as in random positions in each selected block, these positions are AC coefficients of the DCT matrix. The randomness are obtained from a Non-Linear Feedback Shift Register (NLFSR) pseudorandom bit generator that determines in which color component this logo image bits will embed, as well, the block number for hiding each bit has been chosen according to a (semirandom) function proposed in this work.