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1 /* |
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2 * Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of the License "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: |
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15 * |
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16 */ |
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17 |
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18 |
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19 #include "rc2.h" |
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20 #include "rc2table.h" |
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21 #include "../common/inlines.h" |
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22 #include <cryptostrength.h> |
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23 |
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24 const TInt KRC2BlockBytes = 8; |
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25 |
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26 /* CRC2Encryptor */ |
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27 |
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28 void CRC2::SetKey(const TDesC8& aKey, TInt aEffectiveKeyLenBits) |
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29 { |
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30 TUint keyLen = (TUint)aKey.Size(); |
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31 |
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32 iKey.Copy(aKey); |
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33 iEffectiveKeyLenBits = aEffectiveKeyLenBits; |
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34 |
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35 TUint8 L[KRC2MaxKeySizeBytes]; |
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36 Mem::Copy((TUint8*)&L[0], (TUint8*)&aKey[0], keyLen); |
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37 |
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38 TInt maxKeySizeBytes = (TInt)KRC2MaxKeySizeBytes; |
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39 TInt expandedKeyLen = (TInt)KRC2ExpandedKeyLen; |
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40 TInt i = keyLen; |
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41 for (; i < maxKeySizeBytes; i++) |
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42 { |
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43 L[i] = RC2_TABLE::PITABLE[(L[i-1] + L[i-keyLen]) & 255]; |
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44 } |
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45 |
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46 TUint T8 = (aEffectiveKeyLenBits+7) / 8; |
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47 TUint8 TM = (TUint8)(255 >> ((8-(iEffectiveKeyLenBits%8))%8)); |
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48 L[128-T8] = RC2_TABLE::PITABLE[L[128-T8] & TM]; |
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49 |
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50 for (i=127-T8; i>=0; i--) |
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51 L[i] = RC2_TABLE::PITABLE[L[i+1] ^ L[i+T8]]; |
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52 |
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53 for (i=0; i < expandedKeyLen; i++) |
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54 iK[i] = (TUint16)(L[2*i] + (L[2*i+1] << 8)); |
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55 } |
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56 |
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57 void CRC2::Reset() |
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58 { |
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59 SetKey(iKey, iEffectiveKeyLenBits); |
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60 } |
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61 |
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62 TInt CRC2::BlockSize() const |
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63 { |
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64 return KRC2BlockBytes; |
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65 } |
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66 |
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67 TInt CRC2::KeySize() const |
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68 { |
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69 return iKey.Size(); |
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70 } |
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71 |
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72 CRC2::CRC2(void) |
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73 { |
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74 } |
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75 |
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76 /* CRC2Encryptor */ |
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77 |
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78 EXPORT_C CRC2Encryptor* CRC2Encryptor::NewL(const TDesC8& aKey, |
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79 TInt aEffectiveKeyLenBits) |
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80 { |
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81 CRC2Encryptor* me = CRC2Encryptor::NewLC(aKey, aEffectiveKeyLenBits); |
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82 CleanupStack::Pop(me); |
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83 return (me); |
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84 } |
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85 |
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86 EXPORT_C CRC2Encryptor* CRC2Encryptor::NewLC(const TDesC8& aKey, |
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87 TInt aEffectiveKeyLenBits) |
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88 { |
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89 CRC2Encryptor* me = new (ELeave) CRC2Encryptor; |
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90 CleanupStack::PushL(me); // Does not leave but function requires it be Push-ed |
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91 me->SetKey(aKey, aEffectiveKeyLenBits); |
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92 // weak enough if either aKey or aEffectiveKeyLenBits is weak |
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93 TInt minKeySize = Min(aEffectiveKeyLenBits, BytesToBits(aKey.Size())); |
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94 TCrypto::IsSymmetricWeakEnoughL(minKeySize); |
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95 return (me); |
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96 } |
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97 |
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98 #pragma warning (disable : 4244) // conversion from 'int' to 'unsigned short', possible loss of data |
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99 void CRC2Encryptor::Transform(TDes8& aBlock) |
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100 { |
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101 assert(aBlock.Size() == KRC2BlockBytes); |
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102 |
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103 TUint16 R0, R1, R2, R3; |
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104 GetBlockLittleEndian((TUint8*)&aBlock[0], R0, R1, R2, R3); |
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105 |
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106 TInt i = 0; |
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107 for (; i < 16; i++) |
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108 { |
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109 R0 += (R1 & ~R3) + (R2 & R3) + iK[4*i+0]; |
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110 R0 = rotlFixed(R0, 1); |
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111 |
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112 R1 += (R2 & ~R0) + (R3 & R0) + iK[4*i+1]; |
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113 R1 = rotlFixed(R1, 2); |
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114 |
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115 R2 += (R3 & ~R1) + (R0 & R1) + iK[4*i+2]; |
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116 R2 = rotlFixed(R2, 3); |
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117 |
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118 R3 += (R0 & ~R2) + (R1 & R2) + iK[4*i+3]; |
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119 R3 = rotlFixed(R3, 5); |
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120 |
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121 if (i == 4 || i == 10) |
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122 { |
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123 R0 += iK[R3 & 63]; |
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124 R1 += iK[R0 & 63]; |
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125 R2 += iK[R1 & 63]; |
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126 R3 += iK[R2 & 63]; |
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127 } |
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128 } |
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129 |
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130 PutBlockLittleEndian((TUint8*)&aBlock[0], R0, R1, R2, R3); |
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131 } |
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132 #pragma warning (default : 4244) // conversion from 'int' to 'unsigned short', possible loss of data |
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133 |
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134 CRC2Encryptor::CRC2Encryptor(void) |
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135 { |
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136 } |
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137 |
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138 /* CRC2Decryptor */ |
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139 |
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140 EXPORT_C CRC2Decryptor* CRC2Decryptor::NewL(const TDesC8& aKey, |
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141 TInt aEffectiveKeyLenBits) |
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142 { |
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143 CRC2Decryptor* me = CRC2Decryptor::NewLC(aKey, aEffectiveKeyLenBits); |
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144 CleanupStack::Pop(me); |
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145 return (me); |
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146 } |
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147 |
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148 EXPORT_C CRC2Decryptor* CRC2Decryptor::NewLC(const TDesC8& aKey, |
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149 TInt aEffectiveKeyLenBits) |
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150 { |
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151 CRC2Decryptor* me = new (ELeave) CRC2Decryptor; |
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152 CleanupStack::PushL(me); // Does not leave but function requires it be Push-ed |
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153 me->SetKey(aKey, aEffectiveKeyLenBits); |
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154 // weak enough if either aKey or aEffectiveKeyLenBits is weak |
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155 TInt minKeySize = Min(aEffectiveKeyLenBits, BytesToBits(aKey.Size())); |
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156 TCrypto::IsSymmetricWeakEnoughL(minKeySize); |
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157 return (me); |
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158 } |
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159 |
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160 #pragma warning (disable : 4244) // conversion from 'int' to 'unsigned short', possible loss of data |
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161 void CRC2Decryptor::Transform(TDes8& aBlock) |
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162 { |
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163 assert(aBlock.Size() == KRC2BlockBytes); |
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164 |
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165 TUint16 R0, R1, R2, R3; |
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166 GetBlockLittleEndian((TUint8*)&aBlock[0], R0, R1, R2, R3); |
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167 |
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168 TInt i = 15; |
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169 for (; i >= 0; i--) |
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170 { |
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171 if (i == 4 || i == 10) |
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172 { |
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173 R3 -= iK[R2 & 63]; |
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174 R2 -= iK[R1 & 63]; |
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175 R1 -= iK[R0 & 63]; |
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176 R0 -= iK[R3 & 63]; |
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177 } |
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178 |
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179 R3 = rotrFixed(R3, 5); |
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180 R3 -= (R0 & ~R2) + (R1 & R2) + iK[4*i+3]; |
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181 |
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182 R2 = rotrFixed(R2, 3); |
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183 R2 -= (R3 & ~R1) + (R0 & R1) + iK[4*i+2]; |
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184 |
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185 R1 = rotrFixed(R1, 2); |
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186 R1 -= (R2 & ~R0) + (R3 & R0) + iK[4*i+1]; |
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187 |
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188 R0 = rotrFixed(R0, 1); |
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189 R0 -= (R1 & ~R3) + (R2 & R3) + iK[4*i+0]; |
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190 } |
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191 |
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192 PutBlockLittleEndian((TUint8*)&aBlock[0], R0, R1, R2, R3); |
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193 } |
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194 |
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195 #pragma warning (default : 4244) // conversion from 'int' to 'unsigned short', possible loss of data |
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196 |
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197 CRC2Decryptor::CRC2Decryptor(void) |
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198 { |
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199 } |