  In this paper, a novel multi-party quantum private comparison (MQPC) protocol
for equality comparison with n-level single-particle states is constructed,
where the encoded particles are transmitted in a circular way. Here, n parties
employ the qudit shifting operation to encode their private secrets and can
compare the equality of their private secrets within one time execution of
protocol. The proposed MQPC protocol can overcome both the outside attack and
the participant attack. Specially, each party's secret can be kept unknown to
other parties and the third party (TP).
