2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/226780This thesis investigate the channel estimation and the postprocessing of the quantum key distribution protocols. In particular, we propose a new channel estimation procedure, in which we utilize the bit sequences transmitted and received by different bases, and a new postprocessing with two-way classical communication. Then, we show that the key generation rates of the QKD protocols with our channel estimation and/or our postprocessing are higher than those with conventional ones.PhD thesis, March 2009, Tokyo Institute of Technology. 133 pages, 7 figuresQuantum Physicstext