OLD | NEW |
---|---|
(Empty) | |
1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef MEDIA_BASE_ENCRYPTION_SCHEME_H_ | |
6 #define MEDIA_BASE_ENCRYPTION_SCHEME_H_ | |
7 | |
8 #include <stdint.h> | |
9 | |
10 #include "media/base/media_export.h" | |
11 | |
12 namespace media { | |
13 | |
14 // Specification of whether and how the stream is encrypted (in whole or part). | |
15 class MEDIA_EXPORT EncryptionScheme { | |
16 public: | |
17 // Algorithm and mode used for encryption. Allows an indication that no | |
ddorwin
2016/03/03 18:38:04
kCipherModeUnencrypted indicates that no... ?
dougsteed
2016/03/04 19:07:30
Done.
| |
18 // encryption has been applied. | |
19 enum CipherMode { | |
20 kCipherModeUnencrypted, | |
xhwang
2016/03/03 22:33:00
In new code we should use UPPER_CASE for enums:
h
dougsteed
2016/03/04 19:07:30
Prefer consistency with the other enums in media.
xhwang
2016/03/04 20:00:48
Those enums predate the requirement of using UPPER
dougsteed
2016/03/07 17:49:13
I misspoke in my comment about OEMs. I was actuall
| |
21 kCipherModeAesCtr, | |
22 kCipherModeDefault = kCipherModeAesCtr, | |
23 kCipherModeAesCbc, | |
24 kCipherModeMax = kCipherModeAesCbc | |
25 }; | |
26 | |
27 // V3 of the CENC standard adds pattern encryption, through two new | |
28 // protection schemes 'cens' (with AES-CTR) and 'cbcs' (with AES-CBC). | |
29 // The pattern applies only to the 'encrypted' part of the frame (as | |
xhwang
2016/03/03 22:33:00
Does the patter apply to all "encrypted" blocks (a
dougsteed
2016/03/04 19:07:30
Done.
| |
30 // defined by the relevant subsample entries), and reduces further the | |
31 // actual encryption applied through a repeating pattern of (encrypt:skip) | |
32 // 16 byte blocks. For example, in a (1:9) pattern, the first block is | |
33 // encrypted, and the next nine are skipped. This pattern is applied | |
34 // repeatedly until the end of the last 16-byte block in the subsample. | |
35 // Any remaining bytes are left clear. | |
36 // If either or both of encrypt_blocks or skip_blocks is 0, pattern | |
xhwang
2016/03/03 22:33:00
nit: "or both of" is redundant
dougsteed
2016/03/04 19:07:29
Done.
| |
37 // encryption is disabled. | |
38 class PatternSpec { | |
xhwang
2016/03/03 22:33:00
"Spec" is not in the standard and doesn't add any
dougsteed
2016/03/04 19:07:30
Done.
| |
39 public: | |
40 PatternSpec(); | |
41 PatternSpec(uint32_t encrypt_blocks, uint32_t skip_blocks); | |
42 ~PatternSpec(); | |
43 | |
44 bool Matches(const PatternSpec& other) const; | |
45 | |
46 uint32_t encrypt_blocks() const { return encrypt_blocks_; } | |
47 uint32_t skip_blocks() const { return skip_blocks_; } | |
48 | |
49 bool IsInEffect() const; | |
50 | |
51 private: | |
52 uint32_t encrypt_blocks_; | |
53 uint32_t skip_blocks_; | |
54 | |
55 // Allow copy and assignment. | |
56 }; | |
57 | |
58 EncryptionScheme(); | |
59 explicit EncryptionScheme(CipherMode mode); | |
60 EncryptionScheme(CipherMode mode, const PatternSpec& pattern); | |
61 ~EncryptionScheme(); | |
62 | |
63 // Returns an instance of EncryptionScheme indicating no encryption. | |
ddorwin
2016/03/03 18:38:04
This is good, but I meant to add this to the defau
dougsteed
2016/03/04 19:07:30
Done.
| |
64 static EncryptionScheme Unencrypted(); | |
xhwang
2016/03/03 22:33:00
+ddorwin
We use EncryptionScheme::Unencrypted() a
dougsteed
2016/03/04 19:07:30
Done.
| |
65 | |
66 bool Matches(const EncryptionScheme& other) const; | |
67 | |
68 bool is_encrypted() const; | |
xhwang
2016/03/03 22:33:00
nit: you can inline this as well.
dougsteed
2016/03/04 19:07:30
Done.
| |
69 CipherMode mode() const { return mode_; } | |
70 const PatternSpec& pattern() const { return pattern_; } | |
71 | |
72 private: | |
73 CipherMode mode_; | |
xhwang
2016/03/03 22:33:00
You can specify default mode here. Personally I fe
dougsteed
2016/03/04 19:07:30
Done.
| |
74 PatternSpec pattern_; | |
75 | |
76 // Allow copy and assignment. | |
77 }; | |
78 | |
79 } // namespace media | |
80 | |
81 #endif // MEDIA_BASE_ENCRYPTION_SCHEME_H_ | |
OLD | NEW |