In his doctoral thesis[4][2] he showed how quantum entanglement and non-locality can be used to distribute cryptographic keys with perfect security.

At the time he established the first research group in quantum cryptography and computation, based in the Clarendon Laboratory, Oxford.

[5] Also in 2006 was appointed a Lee Kong Chian Centennial Professor at the National University of Singapore[3] and became the founding director of the Centre for Quantum Technologies (CQT).

[7] He has worked with and advised several companies and government agencies, served on various professional advisory boards, and is the Vice Chairman of The Noel Croucher Foundation.

His subsequent work with John Rarity and Paul Tapster, from the Defence Research Agency (DRA) in Malvern, resulted in the proof-of-principle experimental quantum key distribution, introducing parametric down-conversion, phase encoding and quantum interferometry into the repertoire of cryptography.

[12] Ekert and colleagues have made a number of contributions to both theoretical aspects of quantum computation and proposals for its experimental realisations.