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OpenSolaris 2009.06 - man page for crypt (opensolaris section 1)

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crypt(1)				  User Commands 				 crypt(1)

       crypt - encode or decode a file

       crypt [password]

       The crypt utility encrypts and decrypts the contents of a file. crypt reads from the stan-
       dard input and writes on the standard output. The password is a key that selects a partic-
       ular  transformation.  If  no password is given, crypt demands a key from the terminal and
       turns off printing while the key is being typed in. crypt encrypts and decrypts	with  the
       same key:

	 example% crypt key < clear.file > encrypted.file
	 example% crypt key < encrypted.file | pr

       prints the contents of clear.file.

       Files  encrypted  by  crypt are compatible with those treated by the editors ed(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 cleartext 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 widely known, thus crypt
       provides minimal security.

       The transformation of a key into the internal settings  of  the	machine  is  deliberately
       designed  to be expensive, that is, 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.

       Since the key is an argument to the crypt command, it is potentially visible to users exe-
       cuting ps(1) or a derivative command. To minimize this possibility, crypt  takes  care  to
       destroy	any record of the key immediately upon entry. No doubt the choice of keys and key
       security are the most vulnerable aspect of crypt.

       /dev/tty    for typed key

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWcsu			   |

       des(1), ed(1), ex(1), ps(1), vi(1), attributes(5)

SunOS 5.11				    8 Mar 2005					 crypt(1)
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