.\" @(#)xsend.1 6.1 (Berkeley) 4/29/85 .\" .TH XSEND 1 "April 29, 1985" .AT 3 .SH NAME xsend, xget, enroll \- secret mail .SH SYNOPSIS .B xsend person .br .B xget .br .B enroll .SH DESCRIPTION These commands implement a secure communication channel; it is like .IR mail (1), but no one can read the messages except the intended recipient. The method embodies a public-key cryptosystem using knapsacks. .PP To receive messages, use .IR enroll ; it asks you for a password that you must subsequently quote in order to receive secret mail. .PP To receive secret mail, use .IR xget . It asks for your password, then gives you the messages. .PP To send secret mail, use .IR xsend 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. .SH FILES /usr/spool/secretmail/*.key: keys .br /usr/spool/secretmail/*.[0-9]: messages .SH SEE ALSO mail (1) .SH BUGS It should be integrated with ordinary mail. The announcement of secret mail makes traffic analysis possible.