This thesis is concerned with the attempted implementation of online monitoring of computer-transferred messages based on the ministerial draft 192/ME XXV. GP. Embedded in the eighth main piece of the Austrian code of criminal procedure (§§ 109 to 166 StPO), besides regulations on the hearing of evidence, regulations on investigative measures can be found. These include, inter alia, the request for information on telecommunication data as well as the optical and acoustic monitoring. Currently, the Austrian criminal trial law does not know the investigative measure of online monitoring of computer-transferred messages, hence its application would be illegal (§ 5 Abs 1 StPO). Due to the rising number of penal proceedings for acts of terrorism, the federal ministry of justice introduced a ministerial draft to counteract this fact in March 2016. The present diploma thesis examines the ministerial draft 192/ME XXV.GP taking into account the current state of affairs. It gives an insight into the technical as well as the legal limitations which the draft is affected by. In doing so, it focuses on the principle of proportionality, as it is questioned in many answers to the ministerial draft.