The SecureNet box is used to authenticate connections to Plan
9 from a foreign system such as a Unix machine or plain terminal.
The box, which looks like a calculator, performs DES encryption
with a key held in its memory. Another copy of the key is kept
on the authentication server. Each box is protected from
unauthorized use by a four digit PIN.
When the system requires SecureNet authentication, it prompts
with a numerical challenge. The response is compared to one generated
with the key stored on the authentication server. Respond as follows:
Turn on the box and enter your PIN at the EP prompt, followed
by the ENT button. Enter the challenge at Ed prompt, again followed
ENT. Then type to Plan 9 the response generated by the box. If
you make a mistake at any time, reset the box by pressing ON.
The authentication server compares the response
generated by the box to one computed internally. If they match,
the user is accepted.
The box will lose its memory if given the wrong PIN five times
in succession or if its batteries are removed.
To reprogram it, type a 4 at the E0 prompt.
At the E1 prompt, enter your key, which consists of eight three–digit
octal numbers. While you are entering these digits, the box displays
a number ranging from 1 to 8 on the left side of the display.
This number corresponds to the octal number you are entering,
and changes when you enter the first digit of the next
When you are done entering your key, press ENT twice.
At the E2 prompt, enter a PIN for the box.
After you confirm by retyping the PIN at the E3 prompt, you can
use the box as normal.
You can change the PIN using the following procedure. First, turn
on the box and enter your current PIN at the EP prompt. Press
ENT three times; this will return you to the EP prompt. Enter
your PIN again, followed by ENT; you should see a Ed prompt with
a – on the right side of the display. Enter a 0 and press
ENT. You should see the E2 prompt; follow the instructions above
for entering a PIN.
The SecureNet box performs the same encryption as the netcrypt
routine (see encrypt(2)). The entered challenge, a decimal number
between 0 and 100000, is treated as a text string with trailing
binary zero fill to 8 bytes. These 8 bytes are encrypted with
the DES algorithm. The first four bytes are printed on the
display as hexadecimal numbers. However, when set up as described,
the box does not print hexadecimal digits greater than 9. Instead,
it prints a 2 for an A, B, or C, and a 3 for a D, E, or F. If
a 5 rather than a 4 is entered at the E0 print, the hexadecimal
digits are printed. This is not recommended, as letters are too
easily confused with digits on the SecureNet display.|