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<a href="hkdf_8h.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">// hkdf.h - written and placed in public domain by Jeffrey Walton.</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> <span class="comment"></span></div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">/// \file hkdf.h</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">/// \brief Classes for HKDF from RFC 5869</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">/// \since Crypto++ 5.6.3</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment"></span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="preprocessor">#ifndef CRYPTOPP_HKDF_H</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="preprocessor">#define CRYPTOPP_HKDF_H</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> </div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> <span class="preprocessor">#include "<a class="code" href="cryptlib_8h.html">cryptlib.h</a>"</span></div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="preprocessor">#include "<a class="code" href="secblock_8h.html">secblock.h</a>"</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="preprocessor">#include "<a class="code" href="hmac_8h.html">hmac.h</a>"</span></div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> </div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> NAMESPACE_BEGIN(<a class="code" href="namespace_crypto_p_p.html">CryptoPP</a>)</div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> </div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="comment">/// \brief Extract-and-Expand Key Derivation Function (HKDF)</span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="comment"></span><span class="comment">/// \tparam T HashTransformation class</span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="comment"></span><span class="comment">/// \sa <A HREF="http://eprint.iacr.org/2010/264">Cryptographic Extraction and Key</span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> <span class="comment"></span><span class="comment">/// Derivation: The HKDF Scheme</A> and</span></div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="comment"></span><span class="comment">/// <A HREF="http://tools.ietf.org/html/rfc5869">HMAC-based Extract-and-Expand Key</span></div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="comment"></span><span class="comment">/// Derivation Function (HKDF)</A></span></div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="comment"></span><span class="comment">/// \since Crypto++ 5.6.3</span></div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> <span class="comment"></span><span class="keyword">template</span> <<span class="keyword">class</span> T></div><div class="line"><a name="l00024"></a><span class="lineno"><a class="line" href="class_h_k_d_f.html"> 24</a></span> <span class="keyword">class </span><a class="code" href="class_h_k_d_f.html">HKDF</a> : <span class="keyword">public</span> <a class="code" href="class_key_derivation_function.html">KeyDerivationFunction</a></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> {</div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> <span class="keyword">public</span>:</div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span>  <span class="keyword">virtual</span> ~<a class="code" href="class_h_k_d_f.html">HKDF</a>() {}</div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> </div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span>  <span class="keyword">static</span> std::string StaticAlgorithmName () {</div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span>  <span class="keyword">const</span> std::string name(std::string(<span class="stringliteral">"HKDF("</span>) +</div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span>  std::string(T::StaticAlgorithmName()) + std::string(<span class="stringliteral">")"</span>));</div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span>  <span class="keywordflow">return</span> name;</div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span>  }</div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> </div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span>  <span class="comment">// KeyDerivationFunction interface</span></div><div class="line"><a name="l00036"></a><span class="lineno"><a class="line" href="class_h_k_d_f.html#a673b012e36cc09c69c5c5b810068d676"> 36</a></span>  std::string <a class="code" href="class_h_k_d_f.html#a673b012e36cc09c69c5c5b810068d676">AlgorithmName</a>()<span class="keyword"> const </span>{</div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span>  <span class="keywordflow">return</span> StaticAlgorithmName();</div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span>  }</div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span> </div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span>  <span class="comment">// KeyDerivationFunction interface</span></div><div class="line"><a name="l00041"></a><span class="lineno"><a class="line" href="class_h_k_d_f.html#aa7a98f9e475ba73484f5e63299e3623b"> 41</a></span>  <span class="keywordtype">size_t</span> <a class="code" href="class_h_k_d_f.html#aa7a98f9e475ba73484f5e63299e3623b">MaxDerivedLength</a>()<span class="keyword"> const </span>{</div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span>  <span class="keywordflow">return</span> <span class="keyword">static_cast<</span><span class="keywordtype">size_t</span><span class="keyword">></span>(T::DIGESTSIZE) * 255;</div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span>  }</div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span> </div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span>  <span class="comment">// KeyDerivationFunction interface</span></div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span>  <span class="keywordtype">size_t</span> <a class="code" href="class_h_k_d_f.html#a23f6fd8ea5d27c37b18bef25a2f50012">GetValidDerivedLength</a>(<span class="keywordtype">size_t</span> keylength) <span class="keyword">const</span>;</div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span> </div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span>  <span class="comment">// KeyDerivationFunction interface</span></div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span>  <span class="keywordtype">size_t</span> <a class="code" href="class_h_k_d_f.html#a164b826bcba31d1033a0c62f0162efe3">DeriveKey</a>(byte *derived, <span class="keywordtype">size_t</span> derivedLen, <span class="keyword">const</span> byte *secret, <span class="keywordtype">size_t</span> secretLen,</div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span>  <span class="keyword">const</span> <a class="code" href="class_name_value_pairs.html">NameValuePairs</a>& params) <span class="keyword">const</span>;</div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span> <span class="comment"></span></div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span> <span class="comment"> /// \brief Derive a key from a seed</span></div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span> <span class="comment"> /// \param derived the derived output buffer</span></div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span> <span class="comment"> /// \param derivedLen the size of the derived buffer, in bytes</span></div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span> <span class="comment"> /// \param secret the seed input buffer</span></div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span> <span class="comment"> /// \param secretLen the size of the secret buffer, in bytes</span></div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span> <span class="comment"> /// \param salt the salt input buffer</span></div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span> <span class="comment"> /// \param saltLen the size of the salt buffer, in bytes</span></div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span> <span class="comment"> /// \param info the additional input buffer</span></div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span> <span class="comment"> /// \param infoLen the size of the info buffer, in bytes</span></div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span> <span class="comment"> /// \returns the number of iterations performed</span></div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span> <span class="comment"> /// \throws InvalidDerivedLength if <tt>derivedLen</tt> is invalid for the scheme</span></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span> <span class="comment"> /// \details DeriveKey() provides a standard interface to derive a key from</span></div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span> <span class="comment"> /// a seed and other parameters. Each class that derives from KeyDerivationFunction</span></div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span> <span class="comment"> /// provides an overload that accepts most parameters used by the derivation function.</span></div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span> <span class="comment"> /// \details <tt>salt</tt> and <tt>info</tt> can be <tt>nullptr</tt> with 0 length.</span></div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span> <span class="comment"> /// HKDF is unusual in that a non-NULL salt with length 0 is different than a</span></div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span> <span class="comment"> /// NULL <tt>salt</tt>. A NULL <tt>salt</tt> causes HKDF to use a string of 0's</span></div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span> <span class="comment"> /// of length <tt>T::DIGESTSIZE</tt> for the <tt>salt</tt>.</span></div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span> <span class="comment"> /// \details HKDF always returns 1 because it only performs 1 iteration. Other</span></div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span> <span class="comment"> /// derivation functions, like PBKDF's, will return more interesting values.</span></div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span> <span class="comment"></span> <span class="keywordtype">size_t</span> <a class="code" href="class_h_k_d_f.html#a164b826bcba31d1033a0c62f0162efe3">DeriveKey</a>(byte *derived, <span class="keywordtype">size_t</span> derivedLen, <span class="keyword">const</span> byte *secret, <span class="keywordtype">size_t</span> secretLen,</div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span>  <span class="keyword">const</span> byte *salt, <span class="keywordtype">size_t</span> saltLen, <span class="keyword">const</span> byte* info, <span class="keywordtype">size_t</span> infoLen) <span class="keyword">const</span>;</div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span> </div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span> <span class="keyword">protected</span>:</div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span>  <span class="comment">// KeyDerivationFunction interface</span></div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span>  <span class="keyword">const</span> <a class="code" href="class_algorithm.html">Algorithm</a> & GetAlgorithm()<span class="keyword"> const </span>{</div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span>  <span class="keywordflow">return</span> *<span class="keyword">this</span>;</div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span>  }</div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span> </div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span>  <span class="comment">// If salt is absent (NULL), then use the NULL vector. Missing is different than</span></div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span>  <span class="comment">// EMPTY (Non-NULL, 0 length). The length of s_NullVector used depends on the Hash</span></div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span>  <span class="comment">// function. SHA-256 will use 32 bytes of s_NullVector.</span></div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span>  <span class="keyword">typedef</span> byte NullVectorType[T::DIGESTSIZE];</div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span>  <span class="keyword">static</span> <span class="keyword">const</span> NullVectorType& GetNullVector() {</div><div class="line"><a name="l00086"></a><span class="lineno"> 86</span>  <span class="keyword">static</span> <span class="keyword">const</span> NullVectorType s_NullVector = {0};</div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  <span class="keywordflow">return</span> s_NullVector;</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>  }</div><div class="line"><a name="l00089"></a><span class="lineno"> 89</span> };</div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span> </div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span> <span class="keyword">template</span> <<span class="keyword">class</span> T></div><div class="line"><a name="l00092"></a><span class="lineno"><a class="line" href="class_h_k_d_f.html#a23f6fd8ea5d27c37b18bef25a2f50012"> 92</a></span> <span class="keywordtype">size_t</span> <a class="code" href="class_h_k_d_f.html#a23f6fd8ea5d27c37b18bef25a2f50012">HKDF<T>::GetValidDerivedLength</a>(<span class="keywordtype">size_t</span> keylength)<span class="keyword"> const</span></div><div class="line"><a name="l00093"></a><span class="lineno"> 93</span> <span class="keyword"></span>{</div><div class="line"><a name="l00094"></a><span class="lineno"> 94</span>  <span class="keywordflow">if</span> (keylength > MaxDerivedLength())</div><div class="line"><a name="l00095"></a><span class="lineno"> 95</span>  <span class="keywordflow">return</span> MaxDerivedLength();</div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span>  <span class="keywordflow">return</span> keylength;</div><div class="line"><a name="l00097"></a><span class="lineno"> 97</span> }</div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span> </div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span> <span class="keyword">template</span> <<span class="keyword">class</span> T></div><div class="line"><a name="l00100"></a><span class="lineno"><a class="line" href="class_h_k_d_f.html#a164b826bcba31d1033a0c62f0162efe3"> 100</a></span> <span class="keywordtype">size_t</span> <a class="code" href="class_h_k_d_f.html#a164b826bcba31d1033a0c62f0162efe3">HKDF<T>::DeriveKey</a>(byte *derived, <span class="keywordtype">size_t</span> derivedLen,</div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  <span class="keyword">const</span> byte *secret, <span class="keywordtype">size_t</span> secretLen, <span class="keyword">const</span> <a class="code" href="class_name_value_pairs.html">NameValuePairs</a>& params)<span class="keyword"> const</span></div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span> <span class="keyword"></span>{</div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span>  <a class="code" href="trap_8h.html#adf3b392588bc94cbeae9f415a78c7b95">CRYPTOPP_ASSERT</a>(secret && secretLen);</div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span>  <a class="code" href="trap_8h.html#adf3b392588bc94cbeae9f415a78c7b95">CRYPTOPP_ASSERT</a>(derived && derivedLen);</div><div class="line"><a name="l00105"></a><span class="lineno"> 105</span>  <a class="code" href="trap_8h.html#adf3b392588bc94cbeae9f415a78c7b95">CRYPTOPP_ASSERT</a>(derivedLen <= MaxDerivedLength());</div><div class="line"><a name="l00106"></a><span class="lineno"> 106</span> </div><div class="line"><a name="l00107"></a><span class="lineno"> 107</span>  <a class="code" href="class_const_byte_array_parameter.html">ConstByteArrayParameter</a> p;</div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span>  <a class="code" href="class_sec_byte_block.html">SecByteBlock</a> salt, info;</div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span> </div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span>  <span class="keywordflow">if</span> (params.<a class="code" href="class_name_value_pairs.html#a5357c3a09602e44671d1e42cb9a9408d">GetValue</a>(<span class="stringliteral">"Salt"</span>, p))</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span>  salt.<a class="code" href="class_sec_block.html#aaf38f976508a632e2f74aa4f2622da86">Assign</a>(p.<a class="code" href="class_const_byte_array_parameter.html#ab89acc8dae383f2663dd3864651e8ef1">begin</a>(), p.<a class="code" href="class_const_byte_array_parameter.html#ab83dbf7e4d80c0304917a3cc1d3cf144">size</a>());</div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00113"></a><span class="lineno"> 113</span>  salt.<a class="code" href="class_sec_block.html#aaf38f976508a632e2f74aa4f2622da86">Assign</a>(GetNullVector(), T::DIGESTSIZE);</div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span> </div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span>  <span class="keywordflow">if</span> (params.<a class="code" href="class_name_value_pairs.html#a5357c3a09602e44671d1e42cb9a9408d">GetValue</a>(<span class="stringliteral">"Info"</span>, p))</div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span>  info.<a class="code" href="class_sec_block.html#aaf38f976508a632e2f74aa4f2622da86">Assign</a>(p.<a class="code" href="class_const_byte_array_parameter.html#ab89acc8dae383f2663dd3864651e8ef1">begin</a>(), p.<a class="code" href="class_const_byte_array_parameter.html#ab83dbf7e4d80c0304917a3cc1d3cf144">size</a>());</div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span>  info.<a class="code" href="class_sec_block.html#aaf38f976508a632e2f74aa4f2622da86">Assign</a>(GetNullVector(), 0);</div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span> </div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span>  <span class="keywordflow">return</span> DeriveKey(derived, derivedLen, secret, secretLen, salt.<a class="code" href="class_sec_block.html#a11a05906688172579cd3520816799446">begin</a>(), salt.<a class="code" href="class_sec_block.html#af5999bffe3193e62719cc0792b0282a7">size</a>(), info.<a class="code" href="class_sec_block.html#a11a05906688172579cd3520816799446">begin</a>(), info.<a class="code" href="class_sec_block.html#af5999bffe3193e62719cc0792b0282a7">size</a>());</div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span> }</div><div class="line"><a name="l00122"></a><span class="lineno"> 122</span> </div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span> <span class="keyword">template</span> <<span class="keyword">class</span> T></div><div class="line"><a name="l00124"></a><span class="lineno"><a class="line" href="class_h_k_d_f.html#a6f02e8b2a954bf2a87b2e14dafb3643f"> 124</a></span> <span class="keywordtype">size_t</span> <a class="code" href="class_h_k_d_f.html#a164b826bcba31d1033a0c62f0162efe3">HKDF<T>::DeriveKey</a>(byte *derived, <span class="keywordtype">size_t</span> derivedLen, <span class="keyword">const</span> byte *secret, <span class="keywordtype">size_t</span> secretLen,</div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span>  <span class="keyword">const</span> byte *salt, <span class="keywordtype">size_t</span> saltLen, <span class="keyword">const</span> byte* info, <span class="keywordtype">size_t</span> infoLen)<span class="keyword"> const</span></div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span> <span class="keyword"></span>{</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span>  <a class="code" href="trap_8h.html#adf3b392588bc94cbeae9f415a78c7b95">CRYPTOPP_ASSERT</a>(secret && secretLen);</div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>  <a class="code" href="trap_8h.html#adf3b392588bc94cbeae9f415a78c7b95">CRYPTOPP_ASSERT</a>(derived && derivedLen);</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>  <a class="code" href="trap_8h.html#adf3b392588bc94cbeae9f415a78c7b95">CRYPTOPP_ASSERT</a>(derivedLen <= MaxDerivedLength());</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span> </div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  ThrowIfInvalidDerivedLength(derivedLen);</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span> </div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  <span class="comment">// HKDF business logic. NULL is different than empty.</span></div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  <span class="keywordflow">if</span> (salt == NULLPTR)</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span>  {</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>  salt = GetNullVector();</div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span>  saltLen = T::DIGESTSIZE;</div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span>  }</div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span> </div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span>  <span class="comment">// key is PRK from the RFC, salt is IKM from the RFC</span></div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  <a class="code" href="class_h_m_a_c.html">HMAC<T></a> hmac;</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>  <a class="code" href="class_sec_byte_block.html">SecByteBlock</a> key(T::DIGESTSIZE), buffer(T::DIGESTSIZE);</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span> </div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>  <span class="comment">// Extract</span></div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>  hmac.<a class="code" href="class_simple_keying_interface.html#adf3c29b3ef3af74788a58c7c49887fd7">SetKey</a>(salt, saltLen);</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span>  hmac.<a class="code" href="class_hash_transformation.html#af8124c4fca23b74bbdc43660bdae692c">CalculateDigest</a>(key, secret, secretLen);</div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span> </div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>  <span class="comment">// Key</span></div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>  hmac.<a class="code" href="class_simple_keying_interface.html#adf3c29b3ef3af74788a58c7c49887fd7">SetKey</a>(key.begin(), key.size());</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>  byte block = 0;</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span> </div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>  <span class="comment">// Expand</span></div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>  <span class="keywordflow">while</span> (derivedLen > 0)</div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span>  {</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span>  <span class="keywordflow">if</span> (block++) {hmac.<a class="code" href="class_h_m_a_c___base.html#aefb8a1fb43ef8c9390ee89bbb41c83af">Update</a>(buffer, buffer.<a class="code" href="class_sec_block.html#af5999bffe3193e62719cc0792b0282a7">size</a>());}</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  <span class="keywordflow">if</span> (infoLen) {hmac.<a class="code" href="class_h_m_a_c___base.html#aefb8a1fb43ef8c9390ee89bbb41c83af">Update</a>(info, infoLen);}</div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>  hmac.<a class="code" href="class_hash_transformation.html#af8124c4fca23b74bbdc43660bdae692c">CalculateDigest</a>(buffer, &block, 1);</div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span> </div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span> <span class="preprocessor">#if CRYPTOPP_MSC_VERSION</span></div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span>  <span class="keyword">const</span> <span class="keywordtype">size_t</span> digestSize = <span class="keyword">static_cast<</span><span class="keywordtype">size_t</span><span class="keyword">></span>(T::DIGESTSIZE);</div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span>  <span class="keyword">const</span> <span class="keywordtype">size_t</span> segmentLen = <a class="code" href="misc_8h.html#abe412b0409249cb54899e97bc7d86424">STDMIN</a>(derivedLen, digestSize);</div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span>  <a class="code" href="misc_8h.html#a5f6fcbaaf6f72fe46a6d911b033dfea0">memcpy_s</a>(derived, segmentLen, buffer, segmentLen);</div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span> <span class="preprocessor">#else</span></div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span>  <span class="keyword">const</span> <span class="keywordtype">size_t</span> digestSize = <span class="keyword">static_cast<</span><span class="keywordtype">size_t</span><span class="keyword">></span>(T::DIGESTSIZE);</div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span>  <span class="keyword">const</span> <span class="keywordtype">size_t</span> segmentLen = <a class="code" href="misc_8h.html#abe412b0409249cb54899e97bc7d86424">STDMIN</a>(derivedLen, digestSize);</div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>  std::memcpy(derived, buffer, segmentLen);</div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span> <span class="preprocessor">#endif</span></div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span> </div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>  derived += segmentLen;</div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span>  derivedLen -= segmentLen;</div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>  }</div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span> </div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span>  <span class="keywordflow">return</span> 1;</div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span> }</div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span> </div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span> NAMESPACE_END</div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span> </div><div class="line"><a name="l00178"></a><span class="lineno"> 178</span> <span class="preprocessor">#endif // CRYPTOPP_HKDF_H</span></div><div class="ttc" id="class_const_byte_array_parameter_html"><div class="ttname"><a href="class_const_byte_array_parameter.html">ConstByteArrayParameter</a></div><div class="ttdoc">Used to pass byte array input as part of a NameValuePairs object. </div><div class="ttdef"><b>Definition:</b> <a href="algparam_8h_source.html#l00020">algparam.h:20</a></div></div>
<div class="ttc" id="class_simple_keying_interface_html_adf3c29b3ef3af74788a58c7c49887fd7"><div class="ttname"><a href="class_simple_keying_interface.html#adf3c29b3ef3af74788a58c7c49887fd7">SimpleKeyingInterface::SetKey</a></div><div class="ttdeci">virtual void SetKey(const byte *key, size_t length, const NameValuePairs &params=g_nullNameValuePairs)</div><div class="ttdoc">Sets or reset the key of this object. </div><div class="ttdef"><b>Definition:</b> <a href="cryptlib_8cpp_source.html#l00064">cryptlib.cpp:64</a></div></div>
<div class="ttc" id="class_const_byte_array_parameter_html_ab83dbf7e4d80c0304917a3cc1d3cf144"><div class="ttname"><a href="class_const_byte_array_parameter.html#ab83dbf7e4d80c0304917a3cc1d3cf144">ConstByteArrayParameter::size</a></div><div class="ttdeci">size_t size() const</div><div class="ttdoc">Length of the memory block. </div><div class="ttdef"><b>Definition:</b> <a href="algparam_8h_source.html#l00084">algparam.h:84</a></div></div>
<div class="ttc" id="class_h_k_d_f_html_aa7a98f9e475ba73484f5e63299e3623b"><div class="ttname"><a href="class_h_k_d_f.html#aa7a98f9e475ba73484f5e63299e3623b">HKDF::MaxDerivedLength</a></div><div class="ttdeci">size_t MaxDerivedLength() const</div><div class="ttdoc">Determine maximum number of bytes. </div><div class="ttdef"><b>Definition:</b> <a href="hkdf_8h_source.html#l00041">hkdf.h:41</a></div></div>
<div class="ttc" id="class_h_k_d_f_html"><div class="ttname"><a href="class_h_k_d_f.html">HKDF</a></div><div class="ttdoc">Extract-and-Expand Key Derivation Function (HKDF) </div><div class="ttdef"><b>Definition:</b> <a href="hkdf_8h_source.html#l00024">hkdf.h:24</a></div></div>
<div class="ttc" id="cryptlib_8h_html"><div class="ttname"><a href="cryptlib_8h.html">cryptlib.h</a></div><div class="ttdoc">Abstract base classes that provide a uniform interface to this library. </div></div>
<div class="ttc" id="misc_8h_html_a5f6fcbaaf6f72fe46a6d911b033dfea0"><div class="ttname"><a href="misc_8h.html#a5f6fcbaaf6f72fe46a6d911b033dfea0">memcpy_s</a></div><div class="ttdeci">void memcpy_s(void *dest, size_t sizeInBytes, const void *src, size_t count)</div><div class="ttdoc">Bounds checking replacement for memcpy() </div><div class="ttdef"><b>Definition:</b> <a href="misc_8h_source.html#l00383">misc.h:383</a></div></div>
<div class="ttc" id="class_h_k_d_f_html_a164b826bcba31d1033a0c62f0162efe3"><div class="ttname"><a href="class_h_k_d_f.html#a164b826bcba31d1033a0c62f0162efe3">HKDF::DeriveKey</a></div><div class="ttdeci">size_t DeriveKey(byte *derived, size_t derivedLen, const byte *secret, size_t secretLen, const NameValuePairs &params) const</div><div class="ttdoc">Derive a key from a seed. </div><div class="ttdef"><b>Definition:</b> <a href="hkdf_8h_source.html#l00100">hkdf.h:100</a></div></div>
<div class="ttc" id="class_sec_byte_block_html"><div class="ttname"><a href="class_sec_byte_block.html">SecByteBlock</a></div><div class="ttdoc">SecBlock<byte> typedef. </div><div class="ttdef"><b>Definition:</b> <a href="secblock_8h_source.html#l00822">secblock.h:822</a></div></div>
<div class="ttc" id="secblock_8h_html"><div class="ttname"><a href="secblock_8h.html">secblock.h</a></div><div class="ttdoc">Classes and functions for secure memory allocations. </div></div>
<div class="ttc" id="hmac_8h_html"><div class="ttname"><a href="hmac_8h.html">hmac.h</a></div><div class="ttdoc">Classes for HMAC message authentication codes. </div></div>
<div class="ttc" id="class_const_byte_array_parameter_html_ab89acc8dae383f2663dd3864651e8ef1"><div class="ttname"><a href="class_const_byte_array_parameter.html#ab89acc8dae383f2663dd3864651e8ef1">ConstByteArrayParameter::begin</a></div><div class="ttdeci">const byte * begin() const</div><div class="ttdoc">Pointer to the first byte in the memory block. </div><div class="ttdef"><b>Definition:</b> <a href="algparam_8h_source.html#l00080">algparam.h:80</a></div></div>
<div class="ttc" id="class_h_k_d_f_html_a23f6fd8ea5d27c37b18bef25a2f50012"><div class="ttname"><a href="class_h_k_d_f.html#a23f6fd8ea5d27c37b18bef25a2f50012">HKDF::GetValidDerivedLength</a></div><div class="ttdeci">size_t GetValidDerivedLength(size_t keylength) const</div><div class="ttdoc">Returns a valid key length for the derivation function. </div><div class="ttdef"><b>Definition:</b> <a href="hkdf_8h_source.html#l00092">hkdf.h:92</a></div></div>
<div class="ttc" id="class_sec_block_html_aaf38f976508a632e2f74aa4f2622da86"><div class="ttname"><a href="class_sec_block.html#aaf38f976508a632e2f74aa4f2622da86">SecBlock::Assign</a></div><div class="ttdeci">void Assign(const T *ptr, size_type len)</div><div class="ttdoc">Set contents and size from an array. </div><div class="ttdef"><b>Definition:</b> <a href="secblock_8h_source.html#l00605">secblock.h:605</a></div></div>
<div class="ttc" id="class_h_m_a_c___base_html_aefb8a1fb43ef8c9390ee89bbb41c83af"><div class="ttname"><a href="class_h_m_a_c___base.html#aefb8a1fb43ef8c9390ee89bbb41c83af">HMAC_Base::Update</a></div><div class="ttdeci">void Update(const byte *input, size_t length)</div><div class="ttdoc">Updates a hash with additional input. </div><div class="ttdef"><b>Definition:</b> <a href="hmac_8cpp_source.html#l00060">hmac.cpp:60</a></div></div>
<div class="ttc" id="misc_8h_html_abe412b0409249cb54899e97bc7d86424"><div class="ttname"><a href="misc_8h.html#abe412b0409249cb54899e97bc7d86424">STDMIN</a></div><div class="ttdeci">const T & STDMIN(const T &a, const T &b)</div><div class="ttdoc">Replacement function for std::min. </div><div class="ttdef"><b>Definition:</b> <a href="misc_8h_source.html#l00507">misc.h:507</a></div></div>
<div class="ttc" id="trap_8h_html_adf3b392588bc94cbeae9f415a78c7b95"><div class="ttname"><a href="trap_8h.html#adf3b392588bc94cbeae9f415a78c7b95">CRYPTOPP_ASSERT</a></div><div class="ttdeci">#define CRYPTOPP_ASSERT(exp)</div><div class="ttdoc">Debugging and diagnostic assertion. </div><div class="ttdef"><b>Definition:</b> <a href="trap_8h_source.html#l00060">trap.h:60</a></div></div>
<div class="ttc" id="class_sec_block_html_a11a05906688172579cd3520816799446"><div class="ttname"><a href="class_sec_block.html#a11a05906688172579cd3520816799446">SecBlock::begin</a></div><div class="ttdeci">iterator begin()</div><div class="ttdoc">Provides an iterator pointing to the first element in the memory block. </div><div class="ttdef"><b>Definition:</b> <a href="secblock_8h_source.html#l00536">secblock.h:536</a></div></div>
<div class="ttc" id="class_algorithm_html"><div class="ttname"><a href="class_algorithm.html">Algorithm</a></div><div class="ttdoc">Interface for all crypto algorithms. </div><div class="ttdef"><b>Definition:</b> <a href="cryptlib_8h_source.html#l00573">cryptlib.h:573</a></div></div>
<div class="ttc" id="class_hash_transformation_html_af8124c4fca23b74bbdc43660bdae692c"><div class="ttname"><a href="class_hash_transformation.html#af8124c4fca23b74bbdc43660bdae692c">HashTransformation::CalculateDigest</a></div><div class="ttdeci">virtual void CalculateDigest(byte *digest, const byte *input, size_t length)</div><div class="ttdoc">Updates the hash with additional input and computes the hash of the current message. </div><div class="ttdef"><b>Definition:</b> <a href="cryptlib_8h_source.html#l01139">cryptlib.h:1139</a></div></div>
<div class="ttc" id="class_h_m_a_c_html"><div class="ttname"><a href="class_h_m_a_c.html">HMAC</a></div><div class="ttdoc">HMAC. </div><div class="ttdef"><b>Definition:</b> <a href="hmac_8h_source.html#l00050">hmac.h:50</a></div></div>
<div class="ttc" id="namespace_crypto_p_p_html"><div class="ttname"><a href="namespace_crypto_p_p.html">CryptoPP</a></div><div class="ttdoc">Crypto++ library namespace. </div></div>
<div class="ttc" id="class_name_value_pairs_html_a5357c3a09602e44671d1e42cb9a9408d"><div class="ttname"><a href="class_name_value_pairs.html#a5357c3a09602e44671d1e42cb9a9408d">NameValuePairs::GetValue</a></div><div class="ttdeci">bool GetValue(const char *name, T &value) const</div><div class="ttdoc">Get a named value. </div><div class="ttdef"><b>Definition:</b> <a href="cryptlib_8h_source.html#l00347">cryptlib.h:347</a></div></div>
<div class="ttc" id="class_h_k_d_f_html_a673b012e36cc09c69c5c5b810068d676"><div class="ttname"><a href="class_h_k_d_f.html#a673b012e36cc09c69c5c5b810068d676">HKDF::AlgorithmName</a></div><div class="ttdeci">std::string AlgorithmName() const</div><div class="ttdoc">Provides the name of this algorithm. </div><div class="ttdef"><b>Definition:</b> <a href="hkdf_8h_source.html#l00036">hkdf.h:36</a></div></div>
<div class="ttc" id="class_sec_block_html_af5999bffe3193e62719cc0792b0282a7"><div class="ttname"><a href="class_sec_block.html#af5999bffe3193e62719cc0792b0282a7">SecBlock::size</a></div><div class="ttdeci">size_type size() const</div><div class="ttdoc">Provides the count of elements in the SecBlock. </div><div class="ttdef"><b>Definition:</b> <a href="secblock_8h_source.html#l00561">secblock.h:561</a></div></div>
<div class="ttc" id="class_key_derivation_function_html"><div class="ttname"><a href="class_key_derivation_function.html">KeyDerivationFunction</a></div><div class="ttdoc">Interface for key derivation functions. </div><div class="ttdef"><b>Definition:</b> <a href="cryptlib_8h_source.html#l01416">cryptlib.h:1416</a></div></div>
<div class="ttc" id="class_name_value_pairs_html"><div class="ttname"><a href="class_name_value_pairs.html">NameValuePairs</a></div><div class="ttdoc">Interface for retrieving values given their names. </div><div class="ttdef"><b>Definition:</b> <a href="cryptlib_8h_source.html#l00290">cryptlib.h:290</a></div></div>
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