libdcp
key.cc
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1 /*
2  Copyright (C) 2013-2021 Carl Hetherington <cth@carlh.net>
3 
4  This file is part of libdcp.
5 
6  libdcp is free software; you can redistribute it and/or modify
7  it under the terms of the GNU General Public License as published by
8  the Free Software Foundation; either version 2 of the License, or
9  (at your option) any later version.
10 
11  libdcp is distributed in the hope that it will be useful,
12  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  GNU General Public License for more details.
15 
16  You should have received a copy of the GNU General Public License
17  along with libdcp. If not, see <http://www.gnu.org/licenses/>.
18 
19  In addition, as a special exception, the copyright holders give
20  permission to link the code of portions of this program with the
21  OpenSSL library under certain conditions as described in each
22  individual source file, and distribute linked combinations
23  including the two.
24 
25  You must obey the GNU General Public License in all respects
26  for all of the code used other than OpenSSL. If you modify
27  file(s) with this exception, you may extend this exception to your
28  version of the file(s), but you are not obligated to do so. If you
29  do not wish to do so, delete this exception statement from your
30  version. If you delete this exception statement from all source
31  files in the program, then also delete it here.
32 */
33 
34 
40 #include "key.h"
41 #include "dcp_assert.h"
42 #include <asdcp/AS_DCP.h>
43 #include <asdcp/KM_prng.h>
44 #include <asdcp/KM_util.h>
45 #include <string>
46 #include <iomanip>
47 
48 
49 using std::string;
50 using std::setw;
51 using std::setfill;
52 using namespace dcp;
53 
54 
55 Key::Key (int length)
56  : _value (new uint8_t[length])
57  , _length (length)
58 {
59  Kumu::FortunaRNG rng;
60  rng.FillRandom (_value, _length);
61 }
62 
63 
64 Key::Key (uint8_t const * value, int length)
65  : _value (new uint8_t[length])
66  , _length (length)
67 {
68  memcpy (_value, value, _length);
69 }
70 
71 
72 Key::Key (string value)
73  : _value (new uint8_t[value.length() / 2])
74  , _length (value.length() / 2)
75 {
76  unsigned int length_done;
77  Kumu::hex2bin (value.c_str(), _value, _length, &length_done);
78 }
79 
80 
81 Key::Key (Key const & other)
82  : _value (new uint8_t[other._length])
83  , _length (other._length)
84 {
85  memcpy (_value, other._value, _length);
86 }
87 
88 
89 Key::~Key ()
90 {
91  delete[] _value;
92 }
93 
94 
95 Key &
96 Key::operator= (Key const & other)
97 {
98  if (this == &other) {
99  return *this;
100  }
101 
102  _length = other._length;
103  memcpy (_value, other._value, _length);
104  return *this;
105 }
106 
107 
108 string
109 Key::hex () const
110 {
111  char buffer[_length * 2 + 1];
112 
113  char* p = buffer;
114  for (int i = 0; i < _length; ++i) {
115 #ifdef LIBDCP_WINDOWS
116  __mingw_snprintf (p, 3, "%02hhx", _value[i]);
117 #else
118  snprintf (p, 3, "%02hhx", _value[i]);
119 #endif
120  p += 2;
121  }
122 
123  return buffer;
124 }
125 
126 
127 bool
128 dcp::operator== (Key const & a, Key const & b)
129 {
130  return a.length() == b.length() && memcmp(a.value(), b.value(), a.length()) == 0;
131 }
132 
133 
134 bool
135 dcp::operator!= (Key const & a, Key const & b)
136 {
137  return !(a == b);
138 }
A key for decrypting/encrypting assets.
Definition: key.h:59
uint8_t * _value
Definition: key.h:89
std::string hex() const
Definition: key.cc:109
Key(int length=ASDCP::KeyLen)
Definition: key.cc:55
uint8_t const * value() const
Definition: key.h:76
DCP_ASSERT macro.
Key class.
Namespace for everything in libdcp.
Definition: array_data.h:50