Common use of Lessons learned Clause in Contracts

Lessons learned. We here summarise the two most important lessons which need to be taken into account when deriving a key agreement protocol, offering resistance in the CK model and being less vulnerable for DoS attacks. • Resistance in CK model: Any possible definition of the SK should consist of a combination of both the local state variable and the private key of at least one entity. For instance, in [10,11], the SK can be written in a form only consisting of local state variables of the two entities and in [12], the SK is derivable to a form only consisting of the private keys of the two entities. • Resistance to DoS attacks: In [10–12], the SP only retrieves the identity of the SMs after receiving a second message and is not able to detect malicious behaviour. Therefore, to avoid the SP keeping open a huge amount of (potential malicious) sessions, it is better to let the request initiated by the SP. The SM is less vulnerable since it can react when too many requests are sent as they are coming from only one entity, i.e., the SP.