KCIK researchers has contributed to finding that cryptographic key may not be “transitive”  one cannot distribute large amount of key in double distance via any repeater-like protocol using certain quantum states in spite of the fact that these states (called private states) enable point to point secure connection.
We have also introduced a semi-device independent protocol, in which only dimensionality of send signals is assumed to be known . We has contributed to proving the security of such a protocol against detector blinding attacks . KCIK researchers took part in development of a device independent analogue of the SARG protocol of quantum key distribution based on the Hardy’s paradox . S. Bäuml, M. Christandl, K. Horodecki, A. Winter, Limitations on Quantum Key Repeaters, Nature Communications 6, Article number: 6908 (2015).
 M. Pawlowski, N. Brunner, Semi-device-independent security of one-way quantum key distribution, Phys. Rev. A 84, 010302(R) (2011).
 A. Chaturvedi, M. Ray, R. Veynar, M. Pawlowski, Security of QKD protocols against detector blinding attacks, Preprint at http://arxiv.org/abs/1504.00939 (2015).
 R. Rahaman, M.G. Parker, P. Mironowicz, M. Pawłowski, Device-independent quantum key distribution based on measurement inputs, Journal-ref: Phys. Rev. A 92, 062304 (2015).