Image authentication with topologically stable C-point singularities

Optical authentication is a widely adopted approach in optical cryptography due to its inherent parallelism and resistance to digital attacks. We report here a novel, to our knowledge, optical image authentication scheme that utilizes the topological stability and uniqueness of C-point polarization singularity configurations within the vector light fields. C-points are utilized for multi-data encoding, resulting from their topological and polarization degrees of freedom (DOF) originating from their variable spatial distribution and singularity order. Authentication involves image encoding and validation through intensity-based analysis, eliminating the need for interferometric data retrieval. This approach significantly simplifies the optical implementation while maintaining high sensitivity to experimental deviations.