opiekey, otp-md4, otp-md5 - Programs for computing responses to OTP
challenges.
opiekey | otp-md4 | otp-md5 [-v] [-h] [-f] [-x]
[-t type ] [-4|-5] [-a] [-n count ] sequence_number seed
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 key(1) program from
the Bellcore S/Key Version 1 distribution and several of its variants.
-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 [Toc] [Back]
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$
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. opiekey(1) implements simple checks to
reduce the risk of a user making this mistake. Better checks are
needed.
ftpd(8), login(1), opie(4), opiepasswd(1), opieinfo(1), opiekeys(5),
opieaccess(5), opiegen(1) su(1),
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).
OPIE is discussed on the Bellcore "S/Key Users" mailing list. To join,
send an email request to:
[email protected]
7th Edition February 20, 1996 OPIEKEY(1)
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