## Research areas

### Quantum key distribution

#### QKD network integration

Multiuser secure quantum communications over standard optical networks:

QKD over standard metropolitan and passive optical networks based on wavelength-division multiplexing [Ciurana et al, 2014 ], or considering a post-processing step [Martinez-Mateo et al., 2014 ].

Entanglement distribution in optical networks using wavelength-division multiplexing schemes [Ciurana et al, 2015 ].

Secure network coding in the context of QKD: weakly trusted repeaters [Elkouss et al., 2013 ].

#### QKD in next generation network paradigms

Bidirectional integration of QKD systems/networks in software networks: (i) Integration of QKD systems securing future network management and operations in software defined networking and network functions virtualisation architectures. (ii) New applications and service chaining involving QKD systems for secure transactions. (iii) Control plane enabling flexible QKD networks.

#### QKD postprocessing

Shortly presented below, our main contributions to the field of information reconciliation (error correction) in the context of secret-key agreement: **efficient and high-speed information reconciliation** methods proposed for QKD.

Efficient one-way information reconciliation for discrete variable QKD using rate-adaptive low-density parity-check (LDPC) codes [Elkouss et al., 2011 ].

Efficient two-ways information reconciliation for discrete variable QKD using short block-length LDPC codes and an incremental redundancy hybrid ARQ scheme [Martinez-Mateo et al., 2012 ], and an optimized version of Cascade [Martinez-Mateo et al., 2015 ].

High speed information reconciliation for discrete variable QKD using short block-length quasi-cyclic LDPC codes [Martinez-Mateo et al., 2013 ].

Efficient one-way information reconciliation for continuous variable QKD using non-binary LDPC codes defined over a power-of-two finite field [Pacher et al., 2016].