crypt(1)            (Security Administration Utilities)            crypt(1)


   NAME
         crypt - encode/decode

   SYNOPSIS
         crypt [ password ]
         crypt [-k]

   DESCRIPTION
         crypt reads from the standard input and writes on the standard
         output.  The password is a key that selects a particular
         transformation.  If no argument is given, crypt demands a key from
         the terminal and turns off printing while the key is being typed in.
         If the -k option is used, crypt will use the key assigned to the
         environment variable CRYPTKEY.  crypt encrypts and decrypts with the
         same key:

               crypt key <clear >cypher
               crypt key <cypher | pr

         Files encrypted by crypt are compatible with those treated by the
         editors ed(1), edit(1), ex(1), and vi(1) in encryption mode.

         The security of encrypted files depends on three factors:  the
         fundamental method must be hard to solve; direct search of the key
         space must be infeasible; ``sneak paths'' by which keys or clear text
         can become visible must be minimized.

         crypt implements a one-rotor machine designed along the lines of the
         German Enigma, but with a 256-element rotor.  Methods of attack on
         such machines are known, but not widely; moreover the amount of work
         required is likely to be large.

         The transformation of a key into the internal settings of the machine
         is deliberately designed to be expensive, i.e., to take a substantial
         fraction of a second to compute.  However, if keys are restricted to
         (say) three lower-case letters, then encrypted files can be read by
         expending only a substantial fraction of five minutes of machine
         time.

         If the key is an argument to the crypt command, it is potentially
         visible to users executing ps(1) or a derivative.  The choice of keys
         and key security are the most vulnerable aspect of crypt.

   FILES
         /dev/tty  for typed key

   SEE ALSO
         ed(1), edit(1), ex(1), makekey(1), nroff(1), pg(1), ps(1), stty(1),
         vi(1).




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   crypt(1)            (Security Administration Utilities)            crypt(1)


   NOTES
         This command is provided with the Security Administration Utilities,
         which is only available in the United States.  If two or more files
         encrypted with the same key are concatenated and an attempt is made
         to decrypt the result, only the contents of the first of the original
         files will be decrypted correctly.

         If output is piped to nroff and the encryption key is not given on
         the command line then do not pipe crypt through pg(1) or any other
         program that changes the tty settings.  Doing so may cause crypt to
         leave terminal modes in a strange state [see stty(1)].










































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