The present invention relates to various steganographic methods and apparatus. In one embodiment, a plurality of microlenses can provide a steganographic signal for a handheld device. The pattern corresponds to (or conveys) a device identifier. In another embodiment, a handheld computing device includes: a plurality of pixel elements; a set of microlenses; and electronic circuitry communicating with the set of microlenses. The set of microlenses are arranged to create a pattern, the pattern providing a plural-bit identifier. The electronic circuitry operates to change the unique identifier. Other embodiments are also provided.