If one may require information for disclosure in Beis din – is one allowed to record a telephone conversation without the other person’s consent.
Answer:
Although it would not be permitted to tap phones in general, and to listen or publicize others’ conversations (because of prohibitions such as publicizing others’ secrets, the cherem of R. Gershon, heizek re’iah, and others, which are discussed by poskim), it would be permitted for the sake of saving oneself from damage, based on the principle of avid inish dina lenafsheh.
This answer does not address the (secular) legal aspect of phone tapping, and the issue of dina demalchusa.
Sources: See Rav Shlomo Dichovsky, “Ha’azanat Seter”, in Torah Shebe’al Peh 35, p. 57.
