Permutated recovering unused quantum bits

Some quantum key distribution (QKD) technics — BB84, B92 [4], [5] for example — have a gain problem comparing the fnal key to the generated pulses of quantum particles. RUQB [1] technique improves the gain of BB84 by 5.5%, the improvement was achieved by fnding the relationship among the random bits that where initially generated, then exchanging this relationship to aid in recovery of some lost bits. This research permutate the sets that RUQB uses (hence P-RUQB) to have better gain, it was found that about 30% gain can be recovered by using about 8 permutations in ideal situation.