A method for enabling a mobile node to transmit encrypted data over a path including a wireless link and an untrusted link, while avoiding double encryption on any link. The data on the end-to-end path is encrypted using an application specific security mechanism, or an L2 mechanism is used for encrypting the data on the wireless link as mandated by the wireless standards, and an application specific security mechanism is used for encrypting the data on the untrusted link. By avoiding redundant double encryption, the method of the invention results in optimizing the use of network resources in bandwidth-limited wireless networks and increases the life of the mobile node battery.