xref: /curl/lib/curl_des.c (revision 4111d108)
1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) Steve Holme, <steve_holme@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.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  * SPDX-License-Identifier: curl
22  *
23  ***************************************************************************/
24 
25 #include "curl_setup.h"
26 
27 #if defined(USE_CURL_NTLM_CORE) && \
28   (defined(USE_GNUTLS) ||          \
29    defined(USE_SECTRANSP) ||       \
30    defined(USE_OS400CRYPTO) ||     \
31    defined(USE_WIN32_CRYPTO))
32 
33 #include "curl_des.h"
34 
35 /*
36  * Curl_des_set_odd_parity()
37  *
38  * This is used to apply odd parity to the given byte array. It is typically
39  * used by when a cryptography engine does not have its own version.
40  *
41  * The function is a port of the Java based oddParity() function over at:
42  *
43  * https://davenport.sourceforge.net/ntlm.html
44  *
45  * Parameters:
46  *
47  * bytes       [in/out] - The data whose parity bits are to be adjusted for
48  *                        odd parity.
49  * len         [out]    - The length of the data.
50  */
Curl_des_set_odd_parity(unsigned char * bytes,size_t len)51 void Curl_des_set_odd_parity(unsigned char *bytes, size_t len)
52 {
53   size_t i;
54 
55   for(i = 0; i < len; i++) {
56     unsigned char b = bytes[i];
57 
58     bool needs_parity = (((b >> 7) ^ (b >> 6) ^ (b >> 5) ^
59                           (b >> 4) ^ (b >> 3) ^ (b >> 2) ^
60                           (b >> 1)) & 0x01) == 0;
61 
62     if(needs_parity)
63       bytes[i] |= 0x01;
64     else
65       bytes[i] &= 0xfe;
66   }
67 }
68 
69 #endif
70