This paper considers the secure communication issue in an amplify-and-forward relaying cooperative network, in which the energy harvesting relay is powered by radio-frequency signals from the source. Based on the two different energy harvesting strategies, that is, power splitting-based relaying protocols and time switching-based relaying protocols, the authors formulate the problem for maximising the secrecy rate subject to the transmitted power constraint by taking into account the power splitting coefficient and time switching coefficient. The authors solve these problems by applying the semi-definite programming relaxation approach and 1D optimisation over the coefficients of energy harvesting protocols. The simulation results are presented to verify the effectiveness of these solutions proposed in this study.