makekey(1)                                             makekey(1)



     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 lowercase
          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
          (e.g., ed(1) and crypt(1)).  (The encryption scheme provided
          by them is not secure.)  Usually, makekey's input and output
          will be pipes.

     EXAMPLES

               /usr/lib/makekey
               abcdefgh23
               23xq5GyrhLTCA

          The first line invokes makekey, the second line is the input
          to makekey, and the third is the new key generated by make-
          key.

     FILES
          /usr/lib/makekey






     April, 1990                                                     1

     makekey(1)                                             makekey(1)



     SEE ALSO
          crypt(1), ed(1), ex(1), passwd(4).





















































     2                                                     April, 1990