This paper will discuss Science and Technology Investigation draft legislation, especially the part of Source Telecommunication Tapping, from the perspective of law and information security technology. From the legal side, we will introduce the content of the relevant regulations and its influence on the investigation after it is in effective. Then we would move to personal privacy of mobile messengers, which includes the introduction of point-to-point encryption (end-to-end encryption, E2EE), as well as the protection of user content in Popular mobile messengers such as Whatsapp, Telegram, Facebook, LINE, clubhouse. The discussion would then point out the gap between “what the police hacking wants” and “what the police could really get in real world” from the technical perspective.