Shift-invariant maps have been employed to design nonlinear layers in many symmetric cryptographic schemes, such as the χ\chi-map used in Keccak. In this paper, we study the shift-invariant maps on F2n\mathbb{F}_2^n, whose defining functions come from a family of nn-variable Boolean functions induced by a bifix-free sequence a=(a1,a2,,am)F2m\underline{a}=(a_1,a_2,\ldots,a_m)\in \mathbb{F}_2^m with $2\leq m