comparing card-based vaccine credential systems with app-based vaccine credential systems. - Aryan Mahindra; Chandan CV; Priyanshi Katiyar; Anshuman Sharma; Sheshank Shankar; Rohan Sukumaran; Saurish Srivastava; Armaan Bhojwani; Rohan Iyer; Ishaan Singh; Ramesh Raskar (CoRR, 2021)