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1 /*
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2 * sha1.cpp
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3 *
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4 * Copyright (C) 1998, 2009
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5 * Paul E. Jones <paulej@packetizer.com>
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6 * All Rights Reserved.
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7 *
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8 *****************************************************************************
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9 * $Id: sha1.cpp 12 2009-06-22 19:34:25Z paulej $
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10 *****************************************************************************
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11 *
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12 * Description:
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13 * This class implements the Secure Hashing Standard as defined
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14 * in FIPS PUB 180-1 published April 17, 1995.
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15 *
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16 * The Secure Hashing Standard, which uses the Secure Hashing
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17 * Algorithm (SHA), produces a 160-bit message digest for a
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18 * given data stream. In theory, it is highly improbable that
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19 * two messages will produce the same message digest. Therefore,
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20 * this algorithm can serve as a means of providing a "fingerprint"
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21 * for a message.
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22 *
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23 * Portability Issues:
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24 * SHA-1 is defined in terms of 32-bit "words". This code was
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25 * written with the expectation that the processor has at least
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26 * a 32-bit machine word size. If the machine word size is larger,
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27 * the code should still function properly. One caveat to that
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28 * is that the input functions taking characters and character arrays
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29 * assume that only 8 bits of information are stored in each character.
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30 *
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31 * Caveats:
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32 * SHA-1 is designed to work with messages less than 2^64 bits long.
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33 * Although SHA-1 allows a message digest to be generated for
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34 * messages of any number of bits less than 2^64, this implementation
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35 * only works with messages with a length that is a multiple of 8
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36 * bits.
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37 *
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38 */
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39
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40
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41 #include "sha1.h"
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42
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43 /*
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44 * SHA1
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45 *
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46 * Description:
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47 * This is the constructor for the sha1 class.
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48 *
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49 * Parameters:
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50 * None.
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51 *
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52 * Returns:
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53 * Nothing.
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54 *
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55 * Comments:
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56 *
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57 */
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58 SHA1::SHA1()
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59 {
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60 Reset();
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61 }
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62
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63 /*
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64 * ~SHA1
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65 *
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66 * Description:
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67 * This is the destructor for the sha1 class
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68 *
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69 * Parameters:
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70 * None.
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71 *
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72 * Returns:
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73 * Nothing.
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74 *
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75 * Comments:
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76 *
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77 */
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78 SHA1::~SHA1()
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79 {
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80 // The destructor does nothing
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81 }
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82
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83 /*
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84 * Reset
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85 *
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86 * Description:
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87 * This function will initialize the sha1 class member variables
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88 * in preparation for computing a new message digest.
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89 *
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90 * Parameters:
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91 * None.
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92 *
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93 * Returns:
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94 * Nothing.
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95 *
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96 * Comments:
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97 *
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98 */
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99 void SHA1::Reset()
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100 {
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101 Length_Low = 0;
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102 Length_High = 0;
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103 Message_Block_Index = 0;
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104
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105 H[0] = 0x67452301;
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106 H[1] = 0xEFCDAB89;
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107 H[2] = 0x98BADCFE;
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108 H[3] = 0x10325476;
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109 H[4] = 0xC3D2E1F0;
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110
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111 Computed = false;
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112 Corrupted = false;
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113 }
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114
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115 /*
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116 * Result
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117 *
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118 * Description:
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119 * This function will return the 160-bit message digest into the
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120 * array provided.
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121 *
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122 * Parameters:
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123 * message_digest_array: [out]
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124 * This is an array of five unsigned integers which will be filled
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125 * with the message digest that has been computed.
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126 *
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127 * Returns:
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128 * True if successful, false if it failed.
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129 *
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130 * Comments:
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131 *
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132 */
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133 bool SHA1::Result(unsigned *message_digest_array)
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134 {
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135 int i; // Counter
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136
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137 if (Corrupted)
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138 {
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139 return false;
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140 }
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141
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142 if (!Computed)
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143 {
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144 PadMessage();
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145 Computed = true;
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146 }
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147
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148 for(i = 0; i < 5; i++)
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149 {
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150 message_digest_array[i] = H[i];
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151 }
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152
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153 return true;
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154 }
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155
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156 /*
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157 * Input
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158 *
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159 * Description:
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160 * This function accepts an array of octets as the next portion of
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161 * the message.
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162 *
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163 * Parameters:
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164 * message_array: [in]
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165 * An array of characters representing the next portion of the
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166 * message.
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167 *
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168 * Returns:
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169 * Nothing.
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170 *
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171 * Comments:
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172 *
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173 */
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174 void SHA1::Input( const unsigned char *message_array,
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175 unsigned length)
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176 {
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177 if (!length)
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178 {
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179 return;
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180 }
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181
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182 if (Computed || Corrupted)
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183 {
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184 Corrupted = true;
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185 return;
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186 }
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187
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188 while(length-- && !Corrupted)
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189 {
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190 Message_Block[Message_Block_Index++] = (*message_array & 0xFF);
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191
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192 Length_Low += 8;
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193 Length_Low &= 0xFFFFFFFF; // Force it to 32 bits
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194 if (Length_Low == 0)
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195 {
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196 Length_High++;
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197 Length_High &= 0xFFFFFFFF; // Force it to 32 bits
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198 if (Length_High == 0)
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199 {
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200 Corrupted = true; // Message is too long
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201 }
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202 }
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203
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204 if (Message_Block_Index == 64)
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205 {
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206 ProcessMessageBlock();
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207 }
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208
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209 message_array++;
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210 }
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211 }
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212
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213 /*
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214 * Input
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215 *
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216 * Description:
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217 * This function accepts an array of octets as the next portion of
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218 * the message.
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219 *
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220 * Parameters:
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221 * message_array: [in]
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222 * An array of characters representing the next portion of the
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223 * message.
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224 * length: [in]
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225 * The length of the message_array
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226 *
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227 * Returns:
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228 * Nothing.
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229 *
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230 * Comments:
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231 *
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232 */
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233 void SHA1::Input( const char *message_array,
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234 unsigned length)
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235 {
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236 Input((unsigned char *) message_array, length);
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237 }
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238
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239 /*
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240 * Input
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241 *
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242 * Description:
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243 * This function accepts a single octets as the next message element.
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244 *
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245 * Parameters:
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246 * message_element: [in]
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247 * The next octet in the message.
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248 *
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249 * Returns:
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250 * Nothing.
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251 *
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252 * Comments:
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253 *
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254 */
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255 void SHA1::Input(unsigned char message_element)
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256 {
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257 Input(&message_element, 1);
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258 }
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259
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260 /*
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261 * Input
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262 *
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263 * Description:
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264 * This function accepts a single octet as the next message element.
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265 *
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266 * Parameters:
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267 * message_element: [in]
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268 * The next octet in the message.
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269 *
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270 * Returns:
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271 * Nothing.
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272 *
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273 * Comments:
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274 *
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275 */
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276 void SHA1::Input(char message_element)
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277 {
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278 Input((unsigned char *) &message_element, 1);
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279 }
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280
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281 /*
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282 * operator<<
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283 *
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284 * Description:
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285 * This operator makes it convenient to provide character strings to
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286 * the SHA1 object for processing.
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287 *
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288 * Parameters:
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289 * message_array: [in]
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290 * The character array to take as input.
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291 *
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292 * Returns:
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293 * A reference to the SHA1 object.
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294 *
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295 * Comments:
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296 * Each character is assumed to hold 8 bits of information.
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297 *
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298 */
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299 SHA1& SHA1::operator<<(const char *message_array)
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300 {
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301 const char *p = message_array;
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302
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303 while(*p)
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304 {
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305 Input(*p);
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306 p++;
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307 }
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308
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309 return *this;
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310 }
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311
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312 /*
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313 * operator<<
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314 *
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315 * Description:
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316 * This operator makes it convenient to provide character strings to
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317 * the SHA1 object for processing.
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318 *
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319 * Parameters:
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320 * message_array: [in]
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321 * The character array to take as input.
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322 *
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323 * Returns:
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324 * A reference to the SHA1 object.
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325 *
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326 * Comments:
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327 * Each character is assumed to hold 8 bits of information.
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328 *
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329 */
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330 SHA1& SHA1::operator<<(const unsigned char *message_array)
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331 {
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332 const unsigned char *p = message_array;
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333
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334 while(*p)
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335 {
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336 Input(*p);
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337 p++;
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338 }
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339
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340 return *this;
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341 }
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342
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343 /*
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344 * operator<<
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345 *
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346 * Description:
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347 * This function provides the next octet in the message.
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348 *
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349 * Parameters:
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350 * message_element: [in]
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351 * The next octet in the message
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352 *
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353 * Returns:
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354 * A reference to the SHA1 object.
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355 *
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356 * Comments:
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357 * The character is assumed to hold 8 bits of information.
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358 *
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359 */
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360 SHA1& SHA1::operator<<(const char message_element)
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361 {
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362 Input((unsigned char *) &message_element, 1);
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363
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364 return *this;
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365 }
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366
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367 /*
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368 * operator<<
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369 *
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370 * Description:
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371 * This function provides the next octet in the message.
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372 *
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373 * Parameters:
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374 * message_element: [in]
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375 * The next octet in the message
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376 *
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377 * Returns:
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378 * A reference to the SHA1 object.
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379 *
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380 * Comments:
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381 * The character is assumed to hold 8 bits of information.
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382 *
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383 */
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384 SHA1& SHA1::operator<<(const unsigned char message_element)
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385 {
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386 Input(&message_element, 1);
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387
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388 return *this;
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389 }
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390
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391 /*
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392 * ProcessMessageBlock
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393 *
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394 * Description:
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395 * This function will process the next 512 bits of the message
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396 * stored in the Message_Block array.
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397 *
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398 * Parameters:
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399 * None.
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400 *
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401 * Returns:
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402 * Nothing.
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403 *
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404 * Comments:
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405 * Many of the variable names in this function, especially the single
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406 * character names, were used because those were the names used
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407 * in the publication.
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408 *
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409 */
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410 void SHA1::ProcessMessageBlock()
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411 {
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412 const unsigned K[] = { // Constants defined for SHA-1
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413 0x5A827999,
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414 0x6ED9EBA1,
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415 0x8F1BBCDC,
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416 0xCA62C1D6
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417 };
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418 int t; // Loop counter
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419 unsigned temp; // Temporary word value
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420 unsigned W[80]; // Word sequence
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421 unsigned A, B, C, D, E; // Word buffers
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422
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423 /*
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424 * Initialize the first 16 words in the array W
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425 */
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426 for(t = 0; t < 16; t++)
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427 {
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428 W[t] = ((unsigned) Message_Block[t * 4]) << 24;
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429 W[t] |= ((unsigned) Message_Block[t * 4 + 1]) << 16;
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430 W[t] |= ((unsigned) Message_Block[t * 4 + 2]) << 8;
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431 W[t] |= ((unsigned) Message_Block[t * 4 + 3]);
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432 }
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433
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434 for(t = 16; t < 80; t++)
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435 {
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436 W[t] = CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
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437 }
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438
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439 A = H[0];
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440 B = H[1];
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441 C = H[2];
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442 D = H[3];
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443 E = H[4];
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444
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445 for(t = 0; t < 20; t++)
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446 {
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447 temp = CircularShift(5,A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0];
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448 temp &= 0xFFFFFFFF;
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449 E = D;
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450 D = C;
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451 C = CircularShift(30,B);
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452 B = A;
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453 A = temp;
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454 }
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455
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456 for(t = 20; t < 40; t++)
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457 {
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458 temp = CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
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459 temp &= 0xFFFFFFFF;
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460 E = D;
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461 D = C;
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462 C = CircularShift(30,B);
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463 B = A;
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464 A = temp;
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465 }
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466
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467 for(t = 40; t < 60; t++)
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468 {
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469 temp = CircularShift(5,A) +
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470 ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
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471 temp &= 0xFFFFFFFF;
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472 E = D;
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473 D = C;
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474 C = CircularShift(30,B);
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475 B = A;
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476 A = temp;
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477 }
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478
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479 for(t = 60; t < 80; t++)
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480 {
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481 temp = CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
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482 temp &= 0xFFFFFFFF;
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483 E = D;
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484 D = C;
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485 C = CircularShift(30,B);
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486 B = A;
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487 A = temp;
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488 }
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489
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490 H[0] = (H[0] + A) & 0xFFFFFFFF;
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491 H[1] = (H[1] + B) & 0xFFFFFFFF;
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492 H[2] = (H[2] + C) & 0xFFFFFFFF;
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493 H[3] = (H[3] + D) & 0xFFFFFFFF;
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494 H[4] = (H[4] + E) & 0xFFFFFFFF;
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495
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496 Message_Block_Index = 0;
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497 }
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498
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499 /*
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500 * PadMessage
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501 *
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502 * Description:
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503 * According to the standard, the message must be padded to an even
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504 * 512 bits. The first padding bit must be a '1'. The last 64 bits
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|
505 * represent the length of the original message. All bits in between
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|
|
506 * should be 0. This function will pad the message according to those
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|
|
507 * rules by filling the message_block array accordingly. It will also
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|
|
508 * call ProcessMessageBlock() appropriately. When it returns, it
|
|
|
509 * can be assumed that the message digest has been computed.
|
|
|
510 *
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511 * Parameters:
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|
512 * None.
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|
|
513 *
|
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|
514 * Returns:
|
|
|
515 * Nothing.
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|
|
516 *
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517 * Comments:
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|
|
518 *
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|
|
519 */
|
|
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520 void SHA1::PadMessage()
|
|
|
521 {
|
|
|
522 /*
|
|
|
523 * Check to see if the current message block is too small to hold
|
|
|
524 * the initial padding bits and length. If so, we will pad the
|
|
|
525 * block, process it, and then continue padding into a second block.
|
|
|
526 */
|
|
|
527 if (Message_Block_Index > 55)
|
|
|
528 {
|
|
|
529 Message_Block[Message_Block_Index++] = 0x80;
|
|
|
530 while(Message_Block_Index < 64)
|
|
|
531 {
|
|
|
532 Message_Block[Message_Block_Index++] = 0;
|
|
|
533 }
|
|
|
534
|
|
|
535 ProcessMessageBlock();
|
|
|
536
|
|
|
537 while(Message_Block_Index < 56)
|
|
|
538 {
|
|
|
539 Message_Block[Message_Block_Index++] = 0;
|
|
|
540 }
|
|
|
541 }
|
|
|
542 else
|
|
|
543 {
|
|
|
544 Message_Block[Message_Block_Index++] = 0x80;
|
|
|
545 while(Message_Block_Index < 56)
|
|
|
546 {
|
|
|
547 Message_Block[Message_Block_Index++] = 0;
|
|
|
548 }
|
|
|
549
|
|
|
550 }
|
|
|
551
|
|
|
552 /*
|
|
|
553 * Store the message length as the last 8 octets
|
|
|
554 */
|
|
|
555 Message_Block[56] = (Length_High >> 24) & 0xFF;
|
|
|
556 Message_Block[57] = (Length_High >> 16) & 0xFF;
|
|
|
557 Message_Block[58] = (Length_High >> 8) & 0xFF;
|
|
|
558 Message_Block[59] = (Length_High) & 0xFF;
|
|
|
559 Message_Block[60] = (Length_Low >> 24) & 0xFF;
|
|
|
560 Message_Block[61] = (Length_Low >> 16) & 0xFF;
|
|
|
561 Message_Block[62] = (Length_Low >> 8) & 0xFF;
|
|
|
562 Message_Block[63] = (Length_Low) & 0xFF;
|
|
|
563
|
|
|
564 ProcessMessageBlock();
|
|
|
565 }
|
|
|
566
|
|
|
567
|
|
|
568 /*
|
|
|
569 * CircularShift
|
|
|
570 *
|
|
|
571 * Description:
|
|
|
572 * This member function will perform a circular shifting operation.
|
|
|
573 *
|
|
|
574 * Parameters:
|
|
|
575 * bits: [in]
|
|
|
576 * The number of bits to shift (1-31)
|
|
|
577 * word: [in]
|
|
|
578 * The value to shift (assumes a 32-bit integer)
|
|
|
579 *
|
|
|
580 * Returns:
|
|
|
581 * The shifted value.
|
|
|
582 *
|
|
|
583 * Comments:
|
|
|
584 *
|
|
|
585 */
|
|
|
586 unsigned SHA1::CircularShift(int bits, unsigned word)
|
|
|
587 {
|
|
|
588 return ((word << bits) & 0xFFFFFFFF) | ((word & 0xFFFFFFFF) >> (32-bits));
|
|
|
589 }
|
