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1 /* |
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2 * Copyright (c) 2006-2009 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 "arc4impl.h" |
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20 #include "keys.h" |
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21 #include "pluginconfig.h" |
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22 #include "symmetriccipherimpl.h" |
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23 #include <cryptostrength.h> |
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24 #include "common/inlines.h" |
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25 |
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26 |
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27 using namespace SoftwareCrypto; |
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28 |
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29 CArc4Impl* CArc4Impl::NewL(const CKey& aKey, TInt aDiscardBytes) |
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30 { |
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31 CArc4Impl* self = CArc4Impl::NewLC(aKey, aDiscardBytes); |
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32 CleanupStack::Pop(self); |
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33 return self; |
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34 } |
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35 |
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36 CArc4Impl* CArc4Impl::NewLC(const CKey& aKey, TInt aDiscardBytes) |
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37 { |
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38 CArc4Impl* self = new(ELeave) CArc4Impl(aDiscardBytes); |
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39 CleanupStack::PushL(self); |
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40 self->ConstructL(aKey); |
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41 |
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42 const TDesC8& keyContent = aKey.GetTDesC8L(KSymmetricKeyParameterUid); |
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43 TCrypto::IsSymmetricWeakEnoughL(BytesToBits(keyContent.Size()) - keyContent.Size()); |
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44 |
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45 return self; |
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46 } |
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47 |
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48 CArc4Impl::CArc4Impl(TInt aDiscardBytes) |
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49 :ix(1), iy(0), iDiscardBytes(aDiscardBytes) |
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50 { |
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51 } |
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52 |
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53 CArc4Impl::~CArc4Impl() |
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54 { |
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55 } |
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56 |
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57 void CArc4Impl::ConstructL(const CKey& aKey) |
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58 { |
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59 CSymmetricStreamCipherImpl::ConstructL(aKey); |
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60 GenerateSBox(); |
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61 } |
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62 |
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63 CExtendedCharacteristics* CArc4Impl::CreateExtendedCharacteristicsL() |
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64 { |
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65 // All Symbian software plug-ins have unlimited concurrency, cannot be reserved |
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66 // for exclusive use and are not CERTIFIED to be standards compliant. |
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67 return CExtendedCharacteristics::NewL(KMaxTInt, EFalse); |
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68 } |
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69 |
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70 const CExtendedCharacteristics* CArc4Impl::GetExtendedCharacteristicsL() |
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71 { |
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72 return CArc4Impl::CreateExtendedCharacteristicsL(); |
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73 } |
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74 |
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75 void CArc4Impl::DoProcess(TDes8& aData) |
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76 { |
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77 TInt blockLen = aData.Size(); |
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78 |
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79 if (blockLen > 0) |
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80 { |
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81 TUint8* blockPtr = (TUint8*)&aData[0]; |
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82 do |
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83 { |
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84 *blockPtr++ ^= GenerateByte(); |
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85 } |
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86 while (--blockLen); |
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87 } |
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88 } |
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89 |
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90 TBool CArc4Impl::IsValidKeyLength(TInt aKeyBytes) const |
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91 { |
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92 return ((aKeyBytes > 0 && aKeyBytes <= KMaxARC4KeyBytes) ? ETrue : EFalse); |
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93 } |
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94 |
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95 void CArc4Impl::Reset() |
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96 { |
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97 ix = 1; |
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98 iy = 0; |
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99 GenerateSBox(); |
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100 } |
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101 |
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102 TUid CArc4Impl::ImplementationUid() const |
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103 { |
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104 return KCryptoPluginArc4Uid; |
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105 } |
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106 |
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107 TUint8 CArc4Impl::GenerateByte() |
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108 { |
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109 TUint8 a = iState[ix]; |
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110 iy = (TUint8)((iy + a) & 0xff); |
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111 TUint8 b = iState[iy]; |
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112 |
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113 iState[ix] = b; |
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114 iState[iy] = a; |
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115 ix = (TUint8)((ix + 1) & 0xff); |
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116 return (iState[(a + b) & 0xff]); |
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117 } |
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118 |
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119 void CArc4Impl::DiscardBytes(TInt aDiscardBytes) |
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120 { |
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121 if (aDiscardBytes > 0) |
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122 { |
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123 do |
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124 { |
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125 GenerateByte(); |
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126 } |
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127 while(--aDiscardBytes); |
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128 } |
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129 } |
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130 |
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131 void CArc4Impl::GenerateSBox(void) |
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132 { |
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133 TUint keyBytes = iKey->Size(); |
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134 |
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135 TInt i = 0; |
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136 for (; i < KSBoxSize; i++) |
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137 iState[i] = (TUint8)i; |
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138 |
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139 TUint keyIndex = 0, stateIndex = 0; |
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140 i = 0; |
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141 for (; i < KSBoxSize; i++) |
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142 { |
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143 TUint a = iState[i]; |
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144 stateIndex += (*iKey)[keyIndex] + a; |
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145 stateIndex &= 0xff; |
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146 iState[i] = iState[stateIndex]; |
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147 iState[stateIndex] = (TUint8)a; |
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148 if (++keyIndex >= (TUint)keyBytes) |
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149 keyIndex = 0; |
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150 } |
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151 |
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152 DiscardBytes(iDiscardBytes); |
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153 } |