NAME
opiekey, otp-md4, otp-md5 - Programs for computing responses to OTP challenges.
SYNOPSIS
opiekey
|
otp-md4
|
otp-md5
[-v] [-h] [-f] [-x]
[-t
type
] [-4|-5]
[-a] [-n
count
]
sequence_number seed
DESCRIPTION
opiekey
takes the optional count of the number of responses to
print along with a (maximum) sequence number and seed as command line
args. It prompts for the user's secret pass phrase and produces an OPIE
response as six words. If compiled to do so, it can prompt for the user's
secret pass phrase twice to help reduce errors due to mistypes. The second
password entry can be circumvented by entering only an end of line.
opiekey
is downward compatible with the
R key (1)
program from the Bellcore S/Key Version 1 distribution and several of its
variants.
OPTIONS
-v
Display the version number and compile-time options, then exit.
-h
Display a brief help message and exit.
-4, -5
Selects MD4 or MD5, respectively, as the response generation algorithm. The
default for otp-md4 is MD4 and the default for opie-md5 is MD5. The default
for opiekey depends on compile-time configuration, but should be MD5. MD4 is
compatible with the Bellcore S/Key Version 1 distribution.
-f
Force
opiekey
to continue, even where it normally shouldn't. This is currently used to
force opiekey to operate in even from terminals it believes to be insecure.
It can also allow users to disclose their secret pass phrases to attackers.
Use of the -f flag may be disabled by compile-time option in your particular
build of OPIE.
-a
Allows you to input an arbitrary secret pass phrase, instead of running checks
against it. Arbitrary currently does not include '\0' or '\n' characters. This
can be used for backwards compatibility with key generators that do not check
passwords.
-n <count>
the number of one time access passwords to print.
The default is one.
-x
Output the OTPs as hexadecimal numbers instead of six words.
-t <type>
Generate an extended response of the specified type. Supported types are:
word six-word
hex hexadecimal
init hexadecimal re-initialization
init-word six-word re-initialization
The re-initialization responses
always
generate the simple active attack protection.
EXAMPLE
wintermute$ opiekey -5 -n 5 495 wi01309
Using MD5 algorithm to compute response.
Reminder: Don't use opiekey from telnet or dial-in sessions.
Enter secret pass phrase:
491: HOST VET FOWL SEEK IOWA YAP
492: JOB ARTS WERE FEAT TILE IBIS
493: TRUE BRED JOEL USER HALT EBEN
494: HOOD WED MOLT PAN FED RUBY
495: SUB YAW BILE GLEE OWE NOR
wintermute$
BUGS
R opiekey(1)
can lull a user into revealing his/her password when remotely logged in, thus
defeating the purpose of OPIE. This is especially a problem with xterm.
R opiekey(1)
implements simple checks to reduce the risk of a user making
this mistake. Better checks are needed.
SEE ALSO
AUTHOR
Bellcore's S/Key was written by Phil Karn, Neil M. Haller, and John S. Walden
of Bellcore. OPIE was created at NRL by Randall Atkinson, Dan McDonald, and
Craig Metz.
S/Key is a trademark of Bell Communications Research (Bellcore).
CONTACT
OPIE is discussed on the Bellcore "S/Key Users" mailing list. To join,
send an email request to:
skey-users-request@thumper.bellcore.com
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