This letter considers improving end-to-end secrecy capacity of a multihop decode-and-forward relaying system. First, a secrecy rate maximization problem without transmitting artificial noise (AN) is considered, following which the AN-aided secrecy schemes are proposed. Assuming that global channel state information (CSI) is available, an optimal power splitting solution is proposed. Furthermore, an iterative joint optimization of transmit power and power splitting coefficient has also been considered. For the scenario of no eavesdropper's CSI, we provide a suboptimal solution. The simulation results demonstrate that the AN-aided optimal scheme outperforms other schemes.