SKEY(1)                    OpenBSD Reference Manual                    SKEY(1)

NAME
     skey, otp-md4, otp-md5, otp-sha1, otp-rmd160 - respond to an OTP chal-
     lenge

SYNOPSIS
     skey [-x] [-md4 | -md5 | -sha1 | -rmd160] [-n count] [-p passwd] <se-
          quence#>[/] key

DESCRIPTION
     S/Key is a procedure for using one-time passwords to authenticate access
     to computer systems.  It uses 64 bits of information transformed by the
     MD4, MD5, SHA1, or RIPEMD-160 algorithms.  The user supplies the 64 bits
     in the form of 6 English words that are generated by a secure computer.
     This implementation of S/Key is RFC 2289 compliant.

     When skey is invoked as otp-method, skey will use method as the hash
     function where method is currently one of md4, md5, sha1, or rmd160.

     If you misspell your password while running skey, you will get a list of
     passwords that will not work, and no indication of the problem.

     Password sequence numbers count backwards.  You can enter the passwords
     using small letters, even though skey prints them capitalized.

     The options are as follows:

     -n count
             Prints out count one-time passwords.  The default is to print
             one.

     -p password
             Uses password as the secret password.  Use of this option is dis-
             couraged as your secret password could be visible in a process
             listing.

     -x      Causes output to be in hexadecimal instead of ASCII.

     -md4    Selects MD4 as the hash algorithm.

     -md5    Selects MD5 as the hash algorithm.

     -sha1   Selects SHA-1 (NIST Secure Hash Algorithm Revision 1) as the hash
             algorithm.

     -rmd160
             Selects RMD-160 (160 bit Ripe Message Digest) as the hash algo-
             rithm.

EXAMPLES
         % skey 99 th91334
         Enter secret password: <your secret password is entered here>
         OMEN US HORN OMIT BACK AHOY
         %

SEE ALSO
     login(1), skeyinfo(1), skeyinit(1)

     RFC2289

TRADEMARKS AND PATENTS
     S/Key is a Trademark of Bellcore.

AUTHORS
     Phil Karn, Neil M. Haller, John S. Walden, Scott Chasin

OpenBSD 3.0                    October 28, 1993                              1
