The present disclosure is generally related to steganographic encoding and decoding (e.g., data hiding). One claim recites a method including: obtaining media comprising a plurality of line graphics, each of the line graphics comprising one or more contours; obtaining a plural-bit message; obtaining an intermediate signal based at least in part on the plural-bit message; and using a programmed electronic processor, modulating contours of at least some of the plurality of line graphics to steganographically represent the plural-bit message in the media, in which said act of modulating utilizing the intermediate signal to modulate the contours. Of course, other claims and combinations are provided too.