MAKEKEY(8)                                                          MAKEKEY(8)



NAME
       makekey - generate encryption key

SYNOPSIS
       /usr/lib/makekey

DESCRIPTION
       _M_a_k_e_k_e_y  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 (that is, to require a substantial fraction of
       a second).

       The first eight input bytes (the _i_n_p_u_t  _k_e_y)  can  be  arbitrary  ASCII
       characters.   The  last  two (the _s_a_l_t) are best chosen from the set of
       digits, upper- and lower-case letters, and ‘.’ and ‘/’.  The salt char‐
       acters  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 _o_u_t_p_u_t _k_e_y_.

       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 dif‐
       ferent 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.

       _M_a_k_e_k_e_y is intended for programs that perform encryption (for instance,
       _e_d and _c_r_y_p_t(1)).  Usually makekey’s input and output will be pipes.

SEE ALSO
       crypt(1), ed(1)



7th Edition                     April 27, 1985                      MAKEKEY(8)