Comment on "Quantum key distribution for d-level systems with   generalized Bell states" [Phys. Rev. A 65, 052331 (2002)]
  In the paper [Phys. Rev. A 65, 052331(2002)], an entanglement-based quantum key distribution protocol for d-level systems was proposed. However, in this Comment, it is shown that this protocol is insecure for a special attack strategy. 
Fei Gao, Fenzhuo Guo, Qiaoyan Wen, Fuchen Zhu