A computer implemented method for secure transmission of a data message from a source node to a target node

The present invention relates to a computer implemented method (100), performed in a first communication node, for secure transmission of a data message from a source node (302a) to a target node (302f) through one or more intermediate nodes (302b-e), The method (100) comprising: obtaining (S104) situational awareness (SA) data of one or more potential communication nodes, wherein the situational awareness data comprises information about a position and movement of said one or more potential communication nodes, and a classification defining each of said one or more potential communication nodes as either friendly or unfriendly; determining (S114) a routing table of the one or more potential communication nodes, wherein the routing table comprises routing costs of a plurality of transmission paths (P_1 - P_10) between a set of communication node-pairs of the one or more potential communication nodes, and wherein the routing costs are based on the situational awareness data; determining (S116) a routing path from the first communication node to the target node (302f) via one or more selected communication nodes of the one or more potential communication nodes, based on the routing table; and transmitting (S124), in accordance with the determined routing path, the data message to a second communication node of the one or more selected communication nodes, wherein the data message comprises information identifying the target node.