MAKEKEY(8)              GENIX Programmer's Manual              MAKEKEY(8)



      NAME
           makekey - generate encryption key

      SYNOPSIS
           /usr/lib/makekey

      DESCRIPTION
           Makekey improves the usefulness of encryption schemes depending on a
           key  by  increasing  the  amount  of time required to search the key
           space.  It reads 10 bytes from its standard  input,  and  writes  13
           bytes  on its standard output.  The output depends on the input in a
           way intended to be difficult to compute (i.e. to require a  substan-
           tial fraction of a second).

           The first eight input bytes (the input key) can be  arbitrary  ASCII
           characters.  The last two (the salt) are best chosen from the set of
           digits, upper- and lower-case letters, and `.' and  `/'.   The  salt
           characters  are  repeated as the first two characters of the output.
           The remaining 11 output characters are chosen from the same  set  as
           the salt and constitute the output key.

           The transformation performed is essentially the following: the  salt
           is  used  to  select one of 4096 cryptographic machines all based on
           the National Bureau of Standards DES algorithm, but modified in 4096
           different  ways.   Using  the input key as key, a constant string is
           fed into the machine and recirculated a number  of  times.   The  64
           bits  that  come  out are distributed into the 66 useful key bits in
           the result.

           Makekey is intended for programs that perform encryption  (e.g.   ed
           and crypt(1)).  Usually its input and output will be pipes.

      SEE ALSO
           crypt(1), ed(1)





















      Printed 11/16/83                                                        1