IEC/TS 62351-5:2009(E) specifies messages, procedures and algorithms for securing the operation of all protocols based on or derived from the standard IEC 60870-5: Telecontrol equipment and systems - Part 5: Transmission protocols. It more specifically applies to IEC 60870-5-101, IEC 60870-5-102, IEC 60870-5-103, IEC 60870-5-104.
This publication is of core relevance for Smart Grid.