.\" $OpenBSD: skey.1,v 1.3 1996/09/27 15:41:36 millert Exp $
.\"	@(#)skey.1	1.1 	10/28/93
.\"
.Dd 28 October 1993
.Dt SKEY 1
.Os NetBSD 4
.Sh NAME
.Nm S/key
.Nd a one time password system
.Sh DESCRIPTION
.Nm 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 and MD5 algorithms. The user supplies the 64 bits in the form of 6
English words that are generated by a secure computer.
Example use of the S/key program
.Xr skey 1 :
.sp
.sp 0
    % skey  99 th91334
.sp 0
    Enter password: <your secret password is entered here>
.sp 0
    OMEN US HORN OMIT BACK AHOY
.sp 0
    % 
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl x
causes output to be in hexidecimal instead of ASCII.
.It Fl 4
Selects MD4 as the hash algorithm.
.It Fl 5
Selects MD5 as the hash algorithm.
.It Fl n Ar count
Prints out
.Ar count
one time passwords.  The default is to print one.
.It Fl p Ar password
Uses
.Ar password
as the secret password.  Use of this option is discouraged as
your secret password could be visible in a process listing.
.El
.Pp
The programs that are part of the S/Key system are:
.Bl -tag -width skeyinit...
.It Xr skeyinit 1
used to setup your S/Key.
.It Xr skey 1
used to get the one time password each time.
.It Xr skeyinfo 1
used to extract information from the S/Key database.
It tells you what your next challenge will be.
.El
.Pp
When you run
.Xr skeyinit 1
you inform the system of your
secret password.  Running
.Xr skey 1
then generates the
one-time passwords, and also requires your secret
password.  If however, you misspell your password
while running
.Xr skey 1 ,
you will get a list of passwords
that will not work, and no indication about the problem.
.Pp
Password sequence numbers count backward from 99.
You can enter the passwords using small letters, even though
.Xr skey 1
prints them capitalized.
.Sh SEE ALSO
.Xr skeyinit 1 ,
.Xr skeyinfo 1
.Sh AUTHORS
Phil Karn, Neil M. Haller, John S. Walden, Scott Chasin