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DES_CRYPT(3)			    Linux Programmer's Manual			     DES_CRYPT(3)

NAME
       des_crypt, ecb_crypt, cbc_crypt, des_setparity, DES_FAILED - fast DES encryption

SYNOPSIS
       #include <rpc/des_crypt.h>

       int ecb_crypt(char *key, char *data, unsigned datalen,
		     unsigned mode);

       int cbc_crypt(char *key, char *data, unsigned datalen,
		     unsigned mode, char *ivec);

       void des_setparity(char *key);

       int DES_FAILED(int status);

DESCRIPTION
       ecb_crypt()  and cbc_crypt() implement the NBS DES (Data Encryption Standard).  These rou-
       tines are faster and more general purpose than crypt(3).  They also are	able  to  utilize
       DES hardware if it is available.  ecb_crypt() encrypts in ECB (Electronic Code Book) mode,
       which encrypts blocks of data independently.  cbc_crypt() encrypts in  CBC  (Cipher  Block
       Chaining) mode, which chains together successive blocks.  CBC mode protects against inser-
       tions, deletions and substitutions of blocks.  Also, regularities in the clear  text  will
       not appear in the cipher text.

       Here  is how to use these routines.  The first argument, key, is the 8-byte encryption key
       with parity.  To set the key's parity, which for DES is in the low bit of each  byte,  use
       des_setparity().   The  second  argument,  data,  contains  the	data  to  be encrypted or
       decrypted.  The third argument, datalen, is the length in bytes of data, which must  be	a
       multiple  of  8.  The fourth argument, mode, is formed by ORing together some things.  For
       the encryption direction OR in either DES_ENCRYPT or  DES_DECRYPT.   For  software  versus
       hardware  encryption, OR in either DES_HW or DES_SW.  If DES_HW is specified, and there is
       no hardware, then the  encryption  is  performed  in  software  and  the  routine  returns
       DESERR_NOHWDEVICE.  For cbc_crypt(), the argument ivec is the 8-byte initialization vector
       for the chaining.  It is updated to the next initialization vector upon return.

RETURN VALUE
       DESERR_NONE	   No error.
       DESERR_NOHWDEVICE   Encryption succeeded, but done in software instead  of  the	requested
			   hardware.
       DESERR_HWERROR	   An error occurred in the hardware or driver.
       DESERR_BADPARAM	   Bad argument to routine.

       Given  a  result  status  stat, the macro DES_FAILED(stat) is false only for the first two
       statuses.

VERSIONS
       These routines are present in libc 4.6.27 and later, and in glibc 2.1 and later.

ATTRIBUTES
   Multithreading (see pthreads(7))
       The ecb_crypt(), cbc_crypt(), and des_setparity() functions are thread-safe.

CONFORMING TO
       4.3BSD.	Not in POSIX.1-2001.

SEE ALSO
       des(1), crypt(3), xcrypt(3)

COLOPHON
       This page is part of release 3.55 of the Linux man-pages project.  A  description  of  the
       project,     and    information	  about    reporting	bugs,	 can	be    found    at
       http://www.kernel.org/doc/man-pages/.

					    2013-09-18				     DES_CRYPT(3)
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