MAKEKEY(1-SysV)     RISC/os Reference Manual      MAKEKEY(1-SysV)



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 stan-
     dard input, and writes 13 bytes on its standard output.  The
     output depends on the input in a way intended to be diffi-
     cult to compute (i.e., to require a substantial 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, ., /, and upper- and lower-case
     letters.  The salt characters are repeated as the first two
     characters of the output.  The remaining 11 output charac-
     ters 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 4,096 cryptographic
     machines all based on the National Bureau of Standards DES
     algorithm, but broken in 4,096 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 output key bits in the
     result.

     makekey is intended for programs that perform encryption.
     Usually, its input and output will be pipes.

SEE ALSO
     ed(1), crypt(1), vi(1).
     passwd(4) in the Programmer's Reference Manual.

















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