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<div class="title">aes_encryptor.cc</div> </div>
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<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;<span class="comment">// Copyright 2014 Google Inc. All rights reserved.</span></div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span>&#160;<span class="comment">// Use of this source code is governed by a BSD-style</span></div>
<div class="line"><a name="l00004"></a><span class="lineno"> 4</span>&#160;<span class="comment">// license that can be found in the LICENSE file or at</span></div>
<div class="line"><a name="l00005"></a><span class="lineno"> 5</span>&#160;<span class="comment">// https://developers.google.com/open-source/licenses/bsd</span></div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span>&#160;</div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span>&#160;<span class="preprocessor">#include &quot;packager/media/base/aes_encryptor.h&quot;</span></div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span>&#160;</div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span>&#160;<span class="preprocessor">#include &lt;openssl/aes.h&gt;</span></div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span>&#160;</div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;<span class="preprocessor">#include &quot;packager/base/logging.h&quot;</span></div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span>&#160;</div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span>&#160;<span class="keyword">namespace </span>{</div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span>&#160;</div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span>&#160;<span class="comment">// Increment an 8-byte counter by 1. Return true if overflowed.</span></div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160;<span class="keywordtype">bool</span> Increment64(uint8_t* counter) {</div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span>&#160; DCHECK(counter);</div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span>&#160; <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 7; i &gt;= 0; --i) {</div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span>&#160; <span class="keywordflow">if</span> (++counter[i] != 0)</div>
<div class="line"><a name="l00020"></a><span class="lineno"> 20</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00021"></a><span class="lineno"> 21</span>&#160; }</div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160;}</div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160;</div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160;<span class="comment">// AES defines three key sizes: 128, 192 and 256 bits.</span></div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span>&#160;<span class="keywordtype">bool</span> IsKeySizeValidForAes(<span class="keywordtype">size_t</span> key_size) {</div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span>&#160; <span class="keywordflow">return</span> key_size == 16 || key_size == 24 || key_size == 32;</div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span>&#160;}</div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160;</div>
<div class="line"><a name="l00030"></a><span class="lineno"> 30</span>&#160;} <span class="comment">// namespace</span></div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160;</div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160;<span class="keyword">namespace </span>shaka {</div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160;<span class="keyword">namespace </span>media {</div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160;</div>
<div class="line"><a name="l00035"></a><span class="lineno"><a class="line" href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html#a873b0794baca91b36dbc484fc9c37e58"> 35</a></span>&#160;<a class="code" href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html#a873b0794baca91b36dbc484fc9c37e58">AesEncryptor::AesEncryptor</a>(ConstantIvFlag constant_iv_flag)</div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160; : <a class="code" href="../../df/d87/classshaka_1_1media_1_1AesCryptor.html">AesCryptor</a>(constant_iv_flag) {}</div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160;AesEncryptor::~AesEncryptor() {}</div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160;</div>
<div class="line"><a name="l00039"></a><span class="lineno"><a class="line" href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html#a0695df5615cadf6977fdbac978daeffa"> 39</a></span>&#160;<span class="keywordtype">bool</span> <a class="code" href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html#a0695df5615cadf6977fdbac978daeffa">AesEncryptor::InitializeWithIv</a>(<span class="keyword">const</span> std::vector&lt;uint8_t&gt;&amp; key,</div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160; <span class="keyword">const</span> std::vector&lt;uint8_t&gt;&amp; iv) {</div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160; <span class="keywordflow">if</span> (!IsKeySizeValidForAes(key.size())) {</div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Invalid AES key size: &quot;</span> &lt;&lt; key.size();</div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00044"></a><span class="lineno"> 44</span>&#160; }</div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160;</div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span>&#160; CHECK_EQ(AES_set_encrypt_key(key.data(), key.size() * 8, mutable_aes_key()),</div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160; 0);</div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160; <span class="keywordflow">return</span> <a class="code" href="../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a4875146da4761bb757d6b00132ae6fea">SetIv</a>(iv);</div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160;}</div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span>&#160;</div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160;<span class="comment">// We don&#39;t support constant iv for counter mode, as we don&#39;t have a use case</span></div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160;<span class="comment">// for that.</span></div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160;AesCtrEncryptor::AesCtrEncryptor()</div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span>&#160; : <a class="code" href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html">AesEncryptor</a>(kDontUseConstantIv),</div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span>&#160; block_offset_(0),</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160; encrypted_counter_(AES_BLOCK_SIZE, 0) {}</div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160;</div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>&#160;AesCtrEncryptor::~AesCtrEncryptor() {}</div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span>&#160;</div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span>&#160;</div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span>&#160;<span class="keywordtype">bool</span> AesCtrEncryptor::CryptInternal(<span class="keyword">const</span> uint8_t* plaintext,</div>
<div class="line"><a name="l00062"></a><span class="lineno"> 62</span>&#160; <span class="keywordtype">size_t</span> plaintext_size,</div>
<div class="line"><a name="l00063"></a><span class="lineno"> 63</span>&#160; uint8_t* ciphertext,</div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span>&#160; <span class="keywordtype">size_t</span>* ciphertext_size) {</div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span>&#160; DCHECK(plaintext);</div>
<div class="line"><a name="l00066"></a><span class="lineno"> 66</span>&#160; DCHECK(ciphertext);</div>
<div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160; DCHECK(aes_key());</div>
<div class="line"><a name="l00068"></a><span class="lineno"> 68</span>&#160;</div>
<div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&#160; <span class="comment">// |ciphertext_size| is always the same as |plaintext_size| for counter mode.</span></div>
<div class="line"><a name="l00070"></a><span class="lineno"> 70</span>&#160; <span class="keywordflow">if</span> (*ciphertext_size &lt; plaintext_size) {</div>
<div class="line"><a name="l00071"></a><span class="lineno"> 71</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Expecting output size of at least &quot;</span> &lt;&lt; plaintext_size</div>
<div class="line"><a name="l00072"></a><span class="lineno"> 72</span>&#160; &lt;&lt; <span class="stringliteral">&quot; bytes.&quot;</span>;</div>
<div class="line"><a name="l00073"></a><span class="lineno"> 73</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00074"></a><span class="lineno"> 74</span>&#160; }</div>
<div class="line"><a name="l00075"></a><span class="lineno"> 75</span>&#160; *ciphertext_size = plaintext_size;</div>
<div class="line"><a name="l00076"></a><span class="lineno"> 76</span>&#160;</div>
<div class="line"><a name="l00077"></a><span class="lineno"> 77</span>&#160; <span class="keywordflow">for</span> (<span class="keywordtype">size_t</span> i = 0; i &lt; plaintext_size; ++i) {</div>
<div class="line"><a name="l00078"></a><span class="lineno"> 78</span>&#160; <span class="keywordflow">if</span> (block_offset_ == 0) {</div>
<div class="line"><a name="l00079"></a><span class="lineno"> 79</span>&#160; AES_encrypt(&amp;counter_[0], &amp;encrypted_counter_[0], aes_key());</div>
<div class="line"><a name="l00080"></a><span class="lineno"> 80</span>&#160; <span class="comment">// As mentioned in ISO/IEC 23001-7:2016 CENC spec, of the 16 byte counter</span></div>
<div class="line"><a name="l00081"></a><span class="lineno"> 81</span>&#160; <span class="comment">// block, bytes 8 to 15 (i.e. the least significant bytes) are used as a</span></div>
<div class="line"><a name="l00082"></a><span class="lineno"> 82</span>&#160; <span class="comment">// simple 64 bit unsigned integer that is incremented by one for each</span></div>
<div class="line"><a name="l00083"></a><span class="lineno"> 83</span>&#160; <span class="comment">// subsequent block of sample data processed and is kept in network byte</span></div>
<div class="line"><a name="l00084"></a><span class="lineno"> 84</span>&#160; <span class="comment">// order.</span></div>
<div class="line"><a name="l00085"></a><span class="lineno"> 85</span>&#160; Increment64(&amp;counter_[8]);</div>
<div class="line"><a name="l00086"></a><span class="lineno"> 86</span>&#160; }</div>
<div class="line"><a name="l00087"></a><span class="lineno"> 87</span>&#160; ciphertext[i] = plaintext[i] ^ encrypted_counter_[block_offset_];</div>
<div class="line"><a name="l00088"></a><span class="lineno"> 88</span>&#160; block_offset_ = (block_offset_ + 1) % AES_BLOCK_SIZE;</div>
<div class="line"><a name="l00089"></a><span class="lineno"> 89</span>&#160; }</div>
<div class="line"><a name="l00090"></a><span class="lineno"> 90</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a name="l00091"></a><span class="lineno"> 91</span>&#160;}</div>
<div class="line"><a name="l00092"></a><span class="lineno"> 92</span>&#160;</div>
<div class="line"><a name="l00093"></a><span class="lineno"> 93</span>&#160;<span class="keywordtype">void</span> AesCtrEncryptor::SetIvInternal() {</div>
<div class="line"><a name="l00094"></a><span class="lineno"> 94</span>&#160; block_offset_ = 0;</div>
<div class="line"><a name="l00095"></a><span class="lineno"> 95</span>&#160; counter_ = <a class="code" href="../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a96dde16f12a82a563c77f6d5522571f3">iv</a>();</div>
<div class="line"><a name="l00096"></a><span class="lineno"> 96</span>&#160; counter_.resize(AES_BLOCK_SIZE, 0);</div>
<div class="line"><a name="l00097"></a><span class="lineno"> 97</span>&#160;}</div>
<div class="line"><a name="l00098"></a><span class="lineno"> 98</span>&#160;</div>
<div class="line"><a name="l00099"></a><span class="lineno"><a class="line" href="../../d4/d20/classshaka_1_1media_1_1AesCbcEncryptor.html#a2cc8f20b92d884d959b3a586b527fece"> 99</a></span>&#160;<a class="code" href="../../d4/d20/classshaka_1_1media_1_1AesCbcEncryptor.html#a2cc8f20b92d884d959b3a586b527fece">AesCbcEncryptor::AesCbcEncryptor</a>(CbcPaddingScheme padding_scheme)</div>
<div class="line"><a name="l00100"></a><span class="lineno"> 100</span>&#160; : <a class="code" href="../../d4/d20/classshaka_1_1media_1_1AesCbcEncryptor.html">AesCbcEncryptor</a>(padding_scheme, kDontUseConstantIv) {}</div>
<div class="line"><a name="l00101"></a><span class="lineno"> 101</span>&#160;</div>
<div class="line"><a name="l00102"></a><span class="lineno"><a class="line" href="../../d4/d20/classshaka_1_1media_1_1AesCbcEncryptor.html#adbe4df9a37be949487a806301d143230"> 102</a></span>&#160;<a class="code" href="../../d4/d20/classshaka_1_1media_1_1AesCbcEncryptor.html#a2cc8f20b92d884d959b3a586b527fece">AesCbcEncryptor::AesCbcEncryptor</a>(CbcPaddingScheme padding_scheme,</div>
<div class="line"><a name="l00103"></a><span class="lineno"> 103</span>&#160; ConstantIvFlag constant_iv_flag)</div>
<div class="line"><a name="l00104"></a><span class="lineno"> 104</span>&#160; : <a class="code" href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html">AesEncryptor</a>(constant_iv_flag), padding_scheme_(padding_scheme) {</div>
<div class="line"><a name="l00105"></a><span class="lineno"> 105</span>&#160; <span class="keywordflow">if</span> (padding_scheme_ != kNoPadding) {</div>
<div class="line"><a name="l00106"></a><span class="lineno"> 106</span>&#160; CHECK_EQ(constant_iv_flag, kUseConstantIv)</div>
<div class="line"><a name="l00107"></a><span class="lineno"> 107</span>&#160; &lt;&lt; <span class="stringliteral">&quot;non-constant iv (cipher block chain across calls) only makes sense &quot;</span></div>
<div class="line"><a name="l00108"></a><span class="lineno"> 108</span>&#160; <span class="stringliteral">&quot;if the padding_scheme is kNoPadding.&quot;</span>;</div>
<div class="line"><a name="l00109"></a><span class="lineno"> 109</span>&#160; }</div>
<div class="line"><a name="l00110"></a><span class="lineno"> 110</span>&#160;}</div>
<div class="line"><a name="l00111"></a><span class="lineno"> 111</span>&#160;</div>
<div class="line"><a name="l00112"></a><span class="lineno"> 112</span>&#160;AesCbcEncryptor::~AesCbcEncryptor() {}</div>
<div class="line"><a name="l00113"></a><span class="lineno"> 113</span>&#160;</div>
<div class="line"><a name="l00114"></a><span class="lineno"> 114</span>&#160;<span class="keywordtype">bool</span> AesCbcEncryptor::CryptInternal(<span class="keyword">const</span> uint8_t* plaintext,</div>
<div class="line"><a name="l00115"></a><span class="lineno"> 115</span>&#160; <span class="keywordtype">size_t</span> plaintext_size,</div>
<div class="line"><a name="l00116"></a><span class="lineno"> 116</span>&#160; uint8_t* ciphertext,</div>
<div class="line"><a name="l00117"></a><span class="lineno"> 117</span>&#160; <span class="keywordtype">size_t</span>* ciphertext_size) {</div>
<div class="line"><a name="l00118"></a><span class="lineno"> 118</span>&#160; DCHECK(aes_key());</div>
<div class="line"><a name="l00119"></a><span class="lineno"> 119</span>&#160;</div>
<div class="line"><a name="l00120"></a><span class="lineno"> 120</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> residual_block_size = plaintext_size % AES_BLOCK_SIZE;</div>
<div class="line"><a name="l00121"></a><span class="lineno"> 121</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> num_padding_bytes = NumPaddingBytes(plaintext_size);</div>
<div class="line"><a name="l00122"></a><span class="lineno"> 122</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> required_ciphertext_size = plaintext_size + num_padding_bytes;</div>
<div class="line"><a name="l00123"></a><span class="lineno"> 123</span>&#160; <span class="keywordflow">if</span> (*ciphertext_size &lt; required_ciphertext_size) {</div>
<div class="line"><a name="l00124"></a><span class="lineno"> 124</span>&#160; LOG(ERROR) &lt;&lt; <span class="stringliteral">&quot;Expecting output size of at least &quot;</span></div>
<div class="line"><a name="l00125"></a><span class="lineno"> 125</span>&#160; &lt;&lt; required_ciphertext_size &lt;&lt; <span class="stringliteral">&quot; bytes.&quot;</span>;</div>
<div class="line"><a name="l00126"></a><span class="lineno"> 126</span>&#160; <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00127"></a><span class="lineno"> 127</span>&#160; }</div>
<div class="line"><a name="l00128"></a><span class="lineno"> 128</span>&#160; *ciphertext_size = required_ciphertext_size;</div>
<div class="line"><a name="l00129"></a><span class="lineno"> 129</span>&#160;</div>
<div class="line"><a name="l00130"></a><span class="lineno"> 130</span>&#160; <span class="comment">// Encrypt everything but the residual block using CBC.</span></div>
<div class="line"><a name="l00131"></a><span class="lineno"> 131</span>&#160; <span class="keyword">const</span> <span class="keywordtype">size_t</span> cbc_size = plaintext_size - residual_block_size;</div>
<div class="line"><a name="l00132"></a><span class="lineno"> 132</span>&#160; <span class="keywordflow">if</span> (cbc_size != 0) {</div>
<div class="line"><a name="l00133"></a><span class="lineno"> 133</span>&#160; AES_cbc_encrypt(plaintext, ciphertext, cbc_size, aes_key(),</div>
<div class="line"><a name="l00134"></a><span class="lineno"> 134</span>&#160; internal_iv_.data(), AES_ENCRYPT);</div>
<div class="line"><a name="l00135"></a><span class="lineno"> 135</span>&#160; } <span class="keywordflow">else</span> <span class="keywordflow">if</span> (padding_scheme_ == kCtsPadding) {</div>
<div class="line"><a name="l00136"></a><span class="lineno"> 136</span>&#160; <span class="comment">// Don&#39;t have a full block, leave unencrypted.</span></div>
<div class="line"><a name="l00137"></a><span class="lineno"> 137</span>&#160; memcpy(ciphertext, plaintext, plaintext_size);</div>
<div class="line"><a name="l00138"></a><span class="lineno"> 138</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a name="l00139"></a><span class="lineno"> 139</span>&#160; }</div>
<div class="line"><a name="l00140"></a><span class="lineno"> 140</span>&#160; <span class="keywordflow">if</span> (residual_block_size == 0 &amp;&amp; padding_scheme_ != kPkcs5Padding) {</div>
<div class="line"><a name="l00141"></a><span class="lineno"> 141</span>&#160; <span class="comment">// No residual block. No need to do padding.</span></div>
<div class="line"><a name="l00142"></a><span class="lineno"> 142</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a name="l00143"></a><span class="lineno"> 143</span>&#160; }</div>
<div class="line"><a name="l00144"></a><span class="lineno"> 144</span>&#160;</div>
<div class="line"><a name="l00145"></a><span class="lineno"> 145</span>&#160; <span class="keywordflow">if</span> (padding_scheme_ == kNoPadding) {</div>
<div class="line"><a name="l00146"></a><span class="lineno"> 146</span>&#160; <span class="comment">// The residual block is left unencrypted.</span></div>
<div class="line"><a name="l00147"></a><span class="lineno"> 147</span>&#160; memcpy(ciphertext + cbc_size, plaintext + cbc_size, residual_block_size);</div>
<div class="line"><a name="l00148"></a><span class="lineno"> 148</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a name="l00149"></a><span class="lineno"> 149</span>&#160; }</div>
<div class="line"><a name="l00150"></a><span class="lineno"> 150</span>&#160;</div>
<div class="line"><a name="l00151"></a><span class="lineno"> 151</span>&#160; std::vector&lt;uint8_t&gt; residual_block(plaintext + cbc_size,</div>
<div class="line"><a name="l00152"></a><span class="lineno"> 152</span>&#160; plaintext + plaintext_size);</div>
<div class="line"><a name="l00153"></a><span class="lineno"> 153</span>&#160; DCHECK_EQ(residual_block.size(), residual_block_size);</div>
<div class="line"><a name="l00154"></a><span class="lineno"> 154</span>&#160; uint8_t* residual_ciphertext_block = ciphertext + cbc_size;</div>
<div class="line"><a name="l00155"></a><span class="lineno"> 155</span>&#160;</div>
<div class="line"><a name="l00156"></a><span class="lineno"> 156</span>&#160; <span class="keywordflow">if</span> (padding_scheme_ == kPkcs5Padding) {</div>
<div class="line"><a name="l00157"></a><span class="lineno"> 157</span>&#160; DCHECK_EQ(num_padding_bytes, AES_BLOCK_SIZE - residual_block_size);</div>
<div class="line"><a name="l00158"></a><span class="lineno"> 158</span>&#160;</div>
<div class="line"><a name="l00159"></a><span class="lineno"> 159</span>&#160; <span class="comment">// Pad residue block with PKCS5 padding.</span></div>
<div class="line"><a name="l00160"></a><span class="lineno"> 160</span>&#160; residual_block.resize(AES_BLOCK_SIZE, static_cast&lt;char&gt;(num_padding_bytes));</div>
<div class="line"><a name="l00161"></a><span class="lineno"> 161</span>&#160; AES_cbc_encrypt(residual_block.data(), residual_ciphertext_block,</div>
<div class="line"><a name="l00162"></a><span class="lineno"> 162</span>&#160; AES_BLOCK_SIZE, aes_key(), internal_iv_.data(),</div>
<div class="line"><a name="l00163"></a><span class="lineno"> 163</span>&#160; AES_ENCRYPT);</div>
<div class="line"><a name="l00164"></a><span class="lineno"> 164</span>&#160; } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00165"></a><span class="lineno"> 165</span>&#160; DCHECK_EQ(num_padding_bytes, 0u);</div>
<div class="line"><a name="l00166"></a><span class="lineno"> 166</span>&#160; DCHECK_EQ(padding_scheme_, kCtsPadding);</div>
<div class="line"><a name="l00167"></a><span class="lineno"> 167</span>&#160;</div>
<div class="line"><a name="l00168"></a><span class="lineno"> 168</span>&#160; <span class="comment">// Zero-pad the residual block and encrypt using CBC.</span></div>
<div class="line"><a name="l00169"></a><span class="lineno"> 169</span>&#160; residual_block.resize(AES_BLOCK_SIZE, 0);</div>
<div class="line"><a name="l00170"></a><span class="lineno"> 170</span>&#160; AES_cbc_encrypt(residual_block.data(), residual_block.data(),</div>
<div class="line"><a name="l00171"></a><span class="lineno"> 171</span>&#160; AES_BLOCK_SIZE, aes_key(), internal_iv_.data(),</div>
<div class="line"><a name="l00172"></a><span class="lineno"> 172</span>&#160; AES_ENCRYPT);</div>
<div class="line"><a name="l00173"></a><span class="lineno"> 173</span>&#160;</div>
<div class="line"><a name="l00174"></a><span class="lineno"> 174</span>&#160; <span class="comment">// Replace the last full block with the zero-padded, encrypted residual</span></div>
<div class="line"><a name="l00175"></a><span class="lineno"> 175</span>&#160; <span class="comment">// block, and replace the residual block with the equivalent portion of the</span></div>
<div class="line"><a name="l00176"></a><span class="lineno"> 176</span>&#160; <span class="comment">// last full encrypted block. It may appear that some encrypted bits of the</span></div>
<div class="line"><a name="l00177"></a><span class="lineno"> 177</span>&#160; <span class="comment">// last full block are lost, but they are not, as they were used as the IV</span></div>
<div class="line"><a name="l00178"></a><span class="lineno"> 178</span>&#160; <span class="comment">// when encrypting the zero-padded residual block.</span></div>
<div class="line"><a name="l00179"></a><span class="lineno"> 179</span>&#160; memcpy(residual_ciphertext_block,</div>
<div class="line"><a name="l00180"></a><span class="lineno"> 180</span>&#160; residual_ciphertext_block - AES_BLOCK_SIZE, residual_block_size);</div>
<div class="line"><a name="l00181"></a><span class="lineno"> 181</span>&#160; memcpy(residual_ciphertext_block - AES_BLOCK_SIZE, residual_block.data(),</div>
<div class="line"><a name="l00182"></a><span class="lineno"> 182</span>&#160; AES_BLOCK_SIZE);</div>
<div class="line"><a name="l00183"></a><span class="lineno"> 183</span>&#160; }</div>
<div class="line"><a name="l00184"></a><span class="lineno"> 184</span>&#160; <span class="keywordflow">return</span> <span class="keyword">true</span>;</div>
<div class="line"><a name="l00185"></a><span class="lineno"> 185</span>&#160;}</div>
<div class="line"><a name="l00186"></a><span class="lineno"> 186</span>&#160;</div>
<div class="line"><a name="l00187"></a><span class="lineno"> 187</span>&#160;<span class="keywordtype">void</span> AesCbcEncryptor::SetIvInternal() {</div>
<div class="line"><a name="l00188"></a><span class="lineno"> 188</span>&#160; internal_iv_ = <a class="code" href="../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a96dde16f12a82a563c77f6d5522571f3">iv</a>();</div>
<div class="line"><a name="l00189"></a><span class="lineno"> 189</span>&#160; internal_iv_.resize(AES_BLOCK_SIZE, 0);</div>
<div class="line"><a name="l00190"></a><span class="lineno"> 190</span>&#160;}</div>
<div class="line"><a name="l00191"></a><span class="lineno"> 191</span>&#160;</div>
<div class="line"><a name="l00192"></a><span class="lineno"> 192</span>&#160;<span class="keywordtype">size_t</span> AesCbcEncryptor::NumPaddingBytes(<span class="keywordtype">size_t</span> size)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00193"></a><span class="lineno"> 193</span>&#160; <span class="keywordflow">return</span> (padding_scheme_ == kPkcs5Padding)</div>
<div class="line"><a name="l00194"></a><span class="lineno"> 194</span>&#160; ? (AES_BLOCK_SIZE - (size % AES_BLOCK_SIZE))</div>
<div class="line"><a name="l00195"></a><span class="lineno"> 195</span>&#160; : 0;</div>
<div class="line"><a name="l00196"></a><span class="lineno"> 196</span>&#160;}</div>
<div class="line"><a name="l00197"></a><span class="lineno"> 197</span>&#160;</div>
<div class="line"><a name="l00198"></a><span class="lineno"> 198</span>&#160;} <span class="comment">// namespace media</span></div>
<div class="line"><a name="l00199"></a><span class="lineno"> 199</span>&#160;} <span class="comment">// namespace shaka</span></div>
<div class="ttc" id="classshaka_1_1media_1_1AesCryptor_html"><div class="ttname"><a href="../../df/d87/classshaka_1_1media_1_1AesCryptor.html">shaka::media::AesCryptor</a></div><div class="ttdef"><b>Definition:</b> <a href="../../d0/d42/aes__cryptor_8h_source.html#l00025">aes_cryptor.h:25</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1AesCbcEncryptor_html_a2cc8f20b92d884d959b3a586b527fece"><div class="ttname"><a href="../../d4/d20/classshaka_1_1media_1_1AesCbcEncryptor.html#a2cc8f20b92d884d959b3a586b527fece">shaka::media::AesCbcEncryptor::AesCbcEncryptor</a></div><div class="ttdeci">AesCbcEncryptor(CbcPaddingScheme padding_scheme)</div><div class="ttdef"><b>Definition:</b> <a href="../../d5/da4/aes__encryptor_8cc_source.html#l00099">aes_encryptor.cc:99</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1AesEncryptor_html_a0695df5615cadf6977fdbac978daeffa"><div class="ttname"><a href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html#a0695df5615cadf6977fdbac978daeffa">shaka::media::AesEncryptor::InitializeWithIv</a></div><div class="ttdeci">bool InitializeWithIv(const std::vector&lt; uint8_t &gt; &amp;key, const std::vector&lt; uint8_t &gt; &amp;iv) override</div><div class="ttdef"><b>Definition:</b> <a href="../../d5/da4/aes__encryptor_8cc_source.html#l00039">aes_encryptor.cc:39</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1AesEncryptor_html_a873b0794baca91b36dbc484fc9c37e58"><div class="ttname"><a href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html#a873b0794baca91b36dbc484fc9c37e58">shaka::media::AesEncryptor::AesEncryptor</a></div><div class="ttdeci">AesEncryptor(ConstantIvFlag constant_iv_flag)</div><div class="ttdef"><b>Definition:</b> <a href="../../d5/da4/aes__encryptor_8cc_source.html#l00035">aes_encryptor.cc:35</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1AesCbcEncryptor_html"><div class="ttname"><a href="../../d4/d20/classshaka_1_1media_1_1AesCbcEncryptor.html">shaka::media::AesCbcEncryptor</a></div><div class="ttdef"><b>Definition:</b> <a href="../../d1/df0/aes__encryptor_8h_source.html#l00077">aes_encryptor.h:77</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1AesCryptor_html_a96dde16f12a82a563c77f6d5522571f3"><div class="ttname"><a href="../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a96dde16f12a82a563c77f6d5522571f3">shaka::media::AesCryptor::iv</a></div><div class="ttdeci">const std::vector&lt; uint8_t &gt; &amp; iv() const </div><div class="ttdef"><b>Definition:</b> <a href="../../d0/d42/aes__cryptor_8h_source.html#l00081">aes_cryptor.h:81</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1AesCryptor_html_a4875146da4761bb757d6b00132ae6fea"><div class="ttname"><a href="../../df/d87/classshaka_1_1media_1_1AesCryptor.html#a4875146da4761bb757d6b00132ae6fea">shaka::media::AesCryptor::SetIv</a></div><div class="ttdeci">bool SetIv(const std::vector&lt; uint8_t &gt; &amp;iv)</div><div class="ttdef"><b>Definition:</b> <a href="../../d6/d55/aes__cryptor_8cc_source.html#l00067">aes_cryptor.cc:67</a></div></div>
<div class="ttc" id="classshaka_1_1media_1_1AesEncryptor_html"><div class="ttname"><a href="../../d3/d75/classshaka_1_1media_1_1AesEncryptor.html">shaka::media::AesEncryptor</a></div><div class="ttdef"><b>Definition:</b> <a href="../../d1/df0/aes__encryptor_8h_source.html#l00021">aes_encryptor.h:21</a></div></div>
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