Abstract
Research in the area of secure multi-party computation with an unconventional method of using a physical deck of playing cards began in 1989 when den Boer proposed a protocol to compute the logical AND function using five cards. Since then, the area has gained interest from many researchers and several card-based protocols to compute various functions have been developed. In this paper, we propose a card-based protocol called the overwriting protocol that can securely compute the k-candidate n-variable equality function f: {0,1,… ,k-1}ⁿ → {0,1}. We also apply the technique used in this protocol to compute other similar functions.