  We introduce new sophisticated attacks with a Hong-Ou-Mandel interferometer
against quantum key distribution (QKD) and propose a new QKD protocol grafted
with random basis shuffling to block up those attacks. When the polarization
basis is randomly and independently shuffled by sender and receiver, the new
protocol can overcome the attacks even for not-so-weak coherent pulses. We
estimate the number of photons to guarantee the security of the protocol.
