XSEND(1) UNIX Programmer's Manual XSEND(1) NNAAMMEE xsend, xget, enroll - secret mail SSYYNNOOPPSSIISS xxsseenndd person xxggeett eennrroollll DDEESSCCRRIIPPTTIIOONN These commands implement a secure communication channel; it is like _m_a_i_l(1), but no one can read the messages except the intended recipient. The method embodies a public-key cryp- tosystem using knapsacks. To receive messages, use _e_n_r_o_l_l; it asks you for a password that you must subsequently quote in order to receive secret mail. To receive secret mail, use _x_g_e_t. It asks for your pass- word, then gives you the messages. To send secret mail, use _x_s_e_n_d in the same manner as the ordinary mail command. (However, it will accept only one target). A message announcing the receipt of secret mail is also sent by ordinary mail. FFIILLEESS /usr/spool/secretmail/*.key: keys /usr/spool/secretmail/*.[0-9]: messages SSEEEE AALLSSOO mail (1) BBUUGGSS It should be integrated with ordinary mail. The announce- ment of secret mail makes traffic analysis possible. Printed 7/9/88 April 29, 1985 1