Quantum cryptography promises the distribution of cryptographic keys secured by fundamental laws of quantum physics. However, results in quantum hacking have demonstrated that the information theoretic security of quantum cryptography protocols does not guarantee security for actual implementations. Most notable are attacks against the vulnerabilities of single photon detectors [1-4]. In this talk we will report the first proof-of-principle demonstration of a new protocol that removes the threat of any such attack [5]. We demonstrated the protocol over 80 km of spooled fibre as well as across different locations within the city of Calgary [6], confirming this protocol as a realistic approach to secure communication and demonstrating the possibility for controlled two-photon interference in a real-world environment, which is a remaining obstacle to realizing quantum repeaters and quantum networks. [1] Lamas-Linares, A., Kurtsiefer, C. Breaking a quantum key distribution system through a timing side channel, Opt. Express 15 (15), 9388-9393 (2007). [2] Zhao, Y., Fung, C.-H. F., Qi, B., Chen, C. & Lo, H.-K. Quantum Hacking: Experimental demonstration of time-shift attack against practical quantum key distribution systems. Phys. Rev. A 78, 042333 (2008). [3] Lydersen, L., Wiechers, C., Wittmann, C., Elser, D., Skaar, J. & Makarov, V. Hacking commercial quantum cryptography systems by tailored bright illumination. Nature Photonics 4, 686–689 (2010). [4] Lydersen, L., Wiechers, C., Wittmann, C., Elser, D., Skaar, J. & Makarov, V. Thermal blinding of gated detectors in quantum cryptography. Opt. Express 18 (26), 27938-27954 (2010). [5] Lo, H.-K., Curty, M. & Qi, B. Measurement-device-independent quantum key distribution. Phys. Rev. Lett. 108, 130503 (2012). [6] Rubenok, A., Slater, J. A., Chan, P., Lucio-Martinez, I., & Tittel, W. Proof-of-principle field test of quantum key distribution immune to detector attacks. arXiv:1204.0738v1 (2012).