XSEND(1) General Commands Manual XSEND(1)
xsend, xget, enroll - send or receive secret mail
These commands implement a secure communication channel, which is like
mail(1), but no one can read the messages except the intended recipi-
ent. The method embodies a public-key cryptosystem using knapsacks.
To receive messages, use enroll; it asks you for a password that you
must subsequently quote in order to receive secret mail.
To receive secret mail, use xget. It asks for your password, then
gives you the messages.
To send secret mail, use xsend in the same manner as the ordinary mail
command. Unlike mail, xsend accepts only one target. A message
announcing the receipt of secret mail is also sent by ordinary mail.
The knapsack public-key cryptosystem is known to be breakable.
Secret mail should be integrated with ordinary mail.
The announcement of secret mail makes "traffic analysis" possible.
9 September 1987 XSEND(1)