Multi-party Computation with Small Shuffle Complexity Using Regular Polygon Cards

Abstract

It is well-known that a protocol for any function can be constructed using only cards and various shuffling techniques this is referred to as a card-based protocol. In this paper, we propose a new type of cards called regular polygon cards. These cards enable a new encoding for multi-valued inputs while the previous works can only handle binary inputs. We furthermore propose a new technique for constructing a card-based protocol for any n-ary function with small shuffle complexity. This is the first general construction in which the shuffle complexity is independent of the complexity size/depth of the desired functionality, although being directly proportional to the number of inputs. The construction furthermore supports a wide range of cards and encodings, including previously proposed types of cards. Our techniques provide a method for reducing the number of shuffles in card-based protocols.