Hiding data in curves can be achieved by parameterizing a curve using the B-spline model and adding spread spectrum sequences in B-spline control points. In this paper, we propose an iterative alignment-minimization algorithm to perform curve registration and deal with the non-uniqueness of B-spline control points. We demonstrate through experiments the robustness of our method against various attacks such as collusion, geometric transformation, and printingand-scanning. We also show the feasibility of our method for fingerprinting topographic maps and detecting fingerprints from printed copies. 1