opiekey.1: Manual page for the opiekey(1) program.

%%% portions-copyright-cmetz-96
Portions of this software are Copyright 1996-1999 by Craig Metz, All Rights
Reserved. The Inner Net License Version 2 applies to these portions of
the software.
You should have received a copy of the license with this software. If
you didn't get a copy, you may request one from <license@inner.net>.

Portions of this software are Copyright 1995 by Randall Atkinson and Dan
McDonald, All Rights Reserved. All Rights under this copyright are assigned
to the U.S. Naval Research Laboratory (NRL). The NRL Copyright Notice and
License Agreement applies to this software.

History:

Modified by cmetz for OPIE 2.3. Added -t documentation. Removed
opie-bugs pointer. Removed opie-md5 and opie-md4 names. Fixed
a bolding bug. Added -f flag. Added escapes on flags. Minor
editorial changes. Updated example.
Modified by cmetz for OPIE 2.2. Removed MJR DES documentation.
Re-worded retype documentation. Added opiegen reference.
Added -x documentation.
Modified at NRL for OPIE 2.0.
Written at Bellcore for the S/Key Version 1 software distribution
(key.1).

$FreeBSD$
.lt 6.0i
OPIEKEY 1 "February 20, 1996"
.AT 3
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 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
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.

SEE ALSO
ftpd (8), login (1), opie (4), opiepasswd (1), opieinfo (1), opiekeys (5), opieaccess (5), su (1)
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