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.
Cite
@article{arxiv.quant-ph/0406230,
title = {The 'quantum dialogue' can be eavesdropped under the intercept-and-resend attack},
author = {ZhongXiao Man},
journal= {arXiv preprint arXiv:quant-ph/0406230},
year = {2007}
}