Research On Information Reconciliation Basing On Error Correcting Code

Cryptography is a significant technology to ensure information security. Quantum keydistribution and an alternative method that extracted the physical layer characteristics of wirelesschannels for generating secret keys have an attractive foreground. Information reconciliation isan important step in that, with the purpose to transform the two non-identical bit strings (calledraw keys) into two identical ones by exchanging error-correcting information through a publicchannel. However, it presents special problems in regard to error correction of the raw keys.Under the constraint that the public channel can be eavesdropped, classical information on theexchanged quits must be revealed through a series of public discussions. The challenge ofeliminating errors is also depends on preventing the potential eavesdropper reproducing the keyunder the public channel.The error correcting code is widely used in the information reconciliation, which can also beseen as error correction. The main work and contributions are summarized as follows.Firstly, the working principle of information communication, evaluation index and thetheoretical bound of efficiency are discussed. A new method called check bits method based onthe syndrome method and the codeword method is proposed which can reduce the transmissionbits and have well applicability performance and increase the recognition rate of the algorithmevidently. In this paper author also analyze the amount of information leaked in the process ofthe reconciliation.And then, the Winnow algorithm based on Hamming code is analyzed in depth. Furthermorethis paper proposes an improving method, an algorithm which first uses parity–check bits toestimate error rate and then adaptively adjusts the packet length. Compared with the existingWinnow algorithm based on fixed packet length, the improved algorithm has higherreconciliation efficiency and the reconciliation rounds increases slightly.The Low-Density-Parity-Chec（kLDPC）code, is widely used and have well performance in thereconciliation. By analyzing the characteristics of information reconciliation, this paper raisessome methods like improving delete pattern, and also author proposed an error rate adaptivescheme, which was mainly to LDPC codes as a Binary algorithm to tip. And these methods are aset of tradeoffs between efficiency and reconciliation loops.Finally, it is a very important and practical problem that, for the information reconciliation,how to find a code with less coding error, higher coding speed, and flexible coding device.Therefore, a flexible and efficient code, FlexiCode, is introduced to the reconciliation field. Thesimulation results show that it performances worse than the LDPC, but it has a flexible rate change and better performance than Winnow.