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otp-md4(1)

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 particu-
	      lar 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 compati-
	      bility 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
       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 espe-
       cially 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), opiegen(1) 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

7th Edition		       February 20, 1996		    OPIEKEY(1)

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