QoP-ML provides the modelling language for abstracting the cryptographic protocols. All of the security operations/mechanisms which are executed while running cryptographic protocols can be modelled with the QoP-ML. In the QoP-ML, the defined operations can be described by the security metrics which allow performing quality of protection evaluation. Quality of Protection Modelling Language (QoP-ML) provides the modelling language for making abstraction of cryptographic protocols that put emphasis on the details concerning quality of protection. The intended use of QoP-ML is to represent the series of steps which are described as a cryptographic protocol. The QoP-ML introduces the multilevel protocol analysis that extends the possibility of describing the state of the cryptographic protocol. Every single operation defined by the QoPML is described by the security metrics which evaluate the impact of this operation into the overall system security. When the security impact is defined for all actions executed in the protocol, then one can set the protection level for all analysed systems.