Snowden revelations have showed the world how interception, monitoring and blocking are today important tools which need to be legally considered in the context of protection and preservation of cyber security. For protecting the cyber security of computer networks of every sovereign nation, the sovereign nation has to be concerned that its networks are not intercepted, monitored are blocked by other players located outside its territorial boundaries. As such, the legal regimes have to be put in place which can effectively only provide for limited circumstances in which interception, monitoring, blocking and decryption can be legally permissible. Further unauthorised interception, monitoring and blocking has also been made a crime in various jurisdictions. However, these issues need to be elaborated and dealt with in more detail as time passes by.