The 'quantum dialogue' can be eavesdropped under the   intercept-and-resend attack
  In this comment we point out that the 'quantum dialogue' (Phys. Lett. A (in press); quant-ph/0406130) can be eavesdropped under the intercept-and-resend attack. We also give a revised control mode to detect this attack. 
ZhongXiao Man