libdcp
crypto_context.h
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1 /*
2  Copyright (C) 2012-2021 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 #ifndef LIBDCP_CRYPTO_CONTEXT_H
41 #define LIBDCP_CRYPTO_CONTEXT_H
42 
43 
44 #include "key.h"
45 #include "types.h"
46 #include "exceptions.h"
47 #include <asdcp/AS_DCP.h>
48 #include <asdcp/KM_prng.h>
49 #include <boost/optional.hpp>
50 
51 
52 namespace dcp {
53 
54 
55 template <class T>
57 {
58 public:
59  CryptoContext (boost::optional<Key> key, Standard standard)
60  : _context (nullptr)
61  , _hmac (nullptr)
62  {
63  if (!key) {
64  return;
65  }
66 
67  _context = new T ();
68  if (ASDCP_FAILURE (_context->InitKey(key->value()))) {
69  throw MiscError ("could not set up crypto context");
70  }
71 
72  uint8_t cbc_buffer[ASDCP::CBC_BLOCK_SIZE];
73 
74  Kumu::FortunaRNG rng;
75  if (ASDCP_FAILURE (_context->SetIVec (rng.FillRandom (cbc_buffer, ASDCP::CBC_BLOCK_SIZE)))) {
76  throw MiscError ("could not set up CBC initialization vector");
77  }
78 
79  _hmac = new ASDCP::HMACContext;
80 
81  ASDCP::LabelSet_t type;
82  if (standard == Standard::INTEROP) {
83  type = ASDCP::LS_MXF_INTEROP;
84  } else {
85  type = ASDCP::LS_MXF_SMPTE;
86  }
87 
88  if (ASDCP_FAILURE (_hmac->InitKey(key->value(), type))) {
89  throw MiscError ("could not set up HMAC context");
90  }
91  }
92 
93  ~CryptoContext ()
94  {
95  delete _context;
96  delete _hmac;
97  }
98 
99  T* context () const {
100  return _context;
101  }
102 
103  ASDCP::HMACContext* hmac () const {
104  return _hmac;
105  }
106 
107 private:
108  T* _context;
109  ASDCP::HMACContext* _hmac;
110 };
111 
112 
115 
116 
117 }
118 
119 
120 #endif
A miscellaneous exception.
Definition: exceptions.h:94
Exceptions thrown by libdcp.
Key class.
Namespace for everything in libdcp.
Definition: array_data.h:50
Miscellaneous types.