Quantum Cryptography Explained

Makes sense, however one question. Vertical/horizontal photons will only be accurately detected by vertical detectors, but only detected with 50% accuracy for a diagonal detecter. You suggest that based on the key (Key = correct detectors in order given to Bob by Alice), Bob should throw out the bits derived from the 50% accuracy detectors. However my question is, won't throwing out inaccurate bits result in an incorrect result of data? How can you ensure that the data you are throwing out (the 50% accuracy) is replaced properly? 

Let me know whenever you can!

PS: Great video! It's important to know about quantum computing, especially since current cryptography procedures like "One-Way Functions" may not be efficient in encryption with faster computing speeds and stronger processors!