Security of quantum key distribution with iterative sifting

KT acknowledges support from CREST, JST, and H-KL acknowledges financial support from NSERC, US ONR, CFI and ORF. MC gratefully acknowledges support from the Galician Regional Government (program 'Ayudas para proyectos de investigacion desarrollados por investigadores emergentes,' grant No. EM2014/033, and consolidation of Research Units: AtlantTIC), the Spanish Ministry of Economy and Competitiveness (MINECO), and the Fondo Europeo de Desarrollo Regional (FEDER) through grant No. TEC2014-54898-R, and the European Commission (Project QCALL). AM acknowledges support from Grant-in-Aid for JSPS Fellows (KAKENHI Grant No. JP17J04177). C C W Lim acknowledges support from NUS start-up grant R-263-000-C78-133/731.