Can I simulate a particular message format in NS-2 also encrypted

My question is can you implement a particular message format between two nodes in NS-2 like we create a tcp communication but if i want to send particular message eg a certificate with information inside it such as public key or type of node time, etc. i am trying to do it in wireless and want to send a certificate from one node to other which contains key, date, time, message, signed by the node

and also can it be encrypted. is there any example or sample code or snippet or tutorial you can share