In this article, we study the security performance of a mixed radio frequency (RF)-free space optical (FSO) decode-and-forward (DF) relaying system with the simultaneous wireless information and power transfer (SWIPT) technology. The RF channels experience Nakagami- m fading and the FSO channel suffers M?laga turbulence and pointing errors. More precisely, we derive analytical closed-form expressions for the average secrecy capacity and the secrecy outage probability to investigate the security performance of the proposed mixed RF-FSO communication framework with energy harvesting technology.