Technosignature, previously known as SETI(search for extraterrestrial intelligence), is the scientic evidence of past or present extraterrestrial civilizations. Since NRAO's Project Ozma was performed in 1960, most of the noticeable technosignature searches have been done by radio telescopes, hoping to find strong and narrow bandwidth signals that cannot be explained by known natural processes. Recently, the Breakthrough Listen project has opened a new opportunity for technosignature by utilizing both optical telescopes, radio telescopes, and next-generation radio telescope arrays. In this review, mainly based on NASA Technosignatures Workshop (2018), we review the current trends of technosignature surveys, as well as other possible methods for detecting technosignature. Also, we suggest what the Korean community could contribute the technosignature research, including the new SETI project with Korea VLBI Network (KVN).

Since the farside of the moon is a place to avoid arti cial radio frequency interference (RFI) created byhuman civilization, it is a most suitable place for searching technosignature, which are signs of technolog-ical civilization in the universe, in the radio band. The RFI is a factor that makes the study of searchingtechnosignature quite complicated because it is di cult to distinguish between technological signals pro-duced by human and extraterrestrial civilizations. In this paper, we review why the farside of the moon isthe best place to detect technosignature and also introduce radio observatories on the farside of the moonthat have been proposed in radio astronomy. The SETI (Search for Extraterrestrial Intelligence) projecton the farside of the moon is expected to be one of the main candidates for international collaborationresearch topics on lunar surface observatory.