http://g7ee5otfyict57k24vjujuqzi6pd7iwvnsry2mt3svsgwzn6o6iynsad.onion/popets/2021/popets-2021-0039.php
Moreover, vendors receive more purchase data than required for the sake of profiling. We propose a privacy-preserving loyalty program where purchases are always unlinkable, yet a vendor can profile a buyer based on her purchase history, which remains hidden from the vendor.