The Korkine–Zolotarev (KZ) lattice basis reduction algorithm or Hermite-Korkine–Zolotarev (HKZ) algorithm is a lattice reduction algorithm. For lattices in It yields a lattice basis with orthogonality defect at most , unlike the bound of the LLL reduction. KZ has exponential complexity versus the polynomial complexity of the LLL reduction algorithm, however it may still be preferred for solving sequences of Closest Vector Problems (CVPs) in a lattice, where it can be more efficient.