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DES_CRYPT(3)		   Linux Programmers Manual		 DES_CRYPT(3)

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


       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);

       ecb_crypt() and cbc_crypt() implement  the  NBS	DES  (Data  Encryption
       Standard).   These  routines  are  faster and more general purpose than
       crypt(3).  They also are able to utilize DES hardware if it  is	avail
       able.   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 insertions, 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 keys 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 OR ing
       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.

       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.

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

       4.3BSD.	Not in POSIX.1-2001.

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

       This  page  is  part of release 3.05 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/.

				  2007-05-18			  DES_CRYPT(3)

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