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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 2015, Steve Holme, <steve_holme (at) hotmail.com>.
      9  *
     10  * This software is licensed as described in the file COPYING, which
     11  * you should have received as part of this distribution. The terms
     12  * are also available at https://curl.haxx.se/docs/copyright.html.
     13  *
     14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
     15  * copies of the Software, and permit persons to whom the Software is
     16  * furnished to do so, under the terms of the COPYING file.
     17  *
     18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
     19  * KIND, either express or implied.
     20  *
     21  ***************************************************************************/
     22 
     23 #include "curl_setup.h"
     24 
     25 #if defined(USE_NTLM) && !defined(USE_OPENSSL)
     26 
     27 #include "curl_des.h"
     28 
     29 /*
     30  * Curl_des_set_odd_parity()
     31  *
     32  * This is used to apply odd parity to the given byte array. It is typically
     33  * used by when a cryptography engines doesn't have it's own version.
     34  *
     35  * The function is a port of the Java based oddParity() function over at:
     36  *
     37  * https://davenport.sourceforge.io/ntlm.html
     38  *
     39  * Parameters:
     40  *
     41  * bytes       [in/out] - The data whose parity bits are to be adjusted for
     42  *                        odd parity.
     43  * len         [out]    - The length of the data.
     44  */
     45 void Curl_des_set_odd_parity(unsigned char *bytes, size_t len)
     46 {
     47   size_t i;
     48 
     49   for(i = 0; i < len; i++) {
     50     unsigned char b = bytes[i];
     51 
     52     bool needs_parity = (((b >> 7) ^ (b >> 6) ^ (b >> 5) ^
     53                           (b >> 4) ^ (b >> 3) ^ (b >> 2) ^
     54                           (b >> 1)) & 0x01) == 0;
     55 
     56     if(needs_parity)
     57       bytes[i] |= 0x01;
     58     else
     59       bytes[i] &= 0xfe;
     60   }
     61 }
     62 
     63 #endif /* USE_NTLM && !USE_OPENSSL */
     64