Reconciliação de chave do tipo CVQKD utilizando o protocolo CASCADE.

Abstract

The quantum secret key distribution is one of the main practical applications of quantum information theory, making use of quantum mechanics laws’ to ensure unconditional se- curity on information transmission through quantum states and allowing two parties to securely share a secret key with no need for previous shared information. In this work, a solution for secret key reconciliation is presented for keys generated by CVQKD distri- bution schemes using the established CASCADE reconciliatiion protocol. Although it is traditionally applied in the reconciliation of keys generated by DVQKD schemes, which results on bit error rates lower than 0.15, its use is made feasible in the context of continu- ous variables by means of proposed modifications in the initial block size and the number of reconciliation steps executed. This work proposes modifications on fundamental pa- rameters of the reconciliation protocol such that (1) a compleat secret key reconciliation be realized where the bit error rates are lower than 0.25 and (2) a partial reconciliation solution for secret keys with bit error rates greater than 0.25, which aims to control the amount of corrected errors during reconciliation by the amount of leaked information.