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1 local bit = require("bit"); |
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2 |
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3 local public = {}; |
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4 local private = {}; |
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5 |
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6 local aeslua = require("aeslua"); |
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7 aeslua.util = public; |
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8 |
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9 -- |
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10 -- calculate the parity of one byte |
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11 -- |
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12 function public.byteParity(byte) |
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13 byte = bit.bxor(byte, bit.rshift(byte, 4)); |
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14 byte = bit.bxor(byte, bit.rshift(byte, 2)); |
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15 byte = bit.bxor(byte, bit.rshift(byte, 1)); |
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16 return bit.band(byte, 1); |
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17 end |
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18 |
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19 -- |
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20 -- get byte at position index |
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21 -- |
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22 function public.getByte(number, index) |
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23 if (index == 0) then |
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24 return bit.band(number,0xff); |
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25 else |
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26 return bit.band(bit.rshift(number, index*8),0xff); |
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27 end |
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28 end |
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29 |
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30 |
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31 -- |
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32 -- put number into int at position index |
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33 -- |
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34 function public.putByte(number, index) |
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35 if (index == 0) then |
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36 return bit.band(number,0xff); |
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37 else |
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38 return bit.lshift(bit.band(number,0xff),index*8); |
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39 end |
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40 end |
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41 |
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42 -- |
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43 -- convert byte array to int array |
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44 -- |
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45 function public.bytesToInts(bytes, start, n) |
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46 local ints = {}; |
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47 for i = 0, n - 1 do |
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48 ints[i] = public.putByte(bytes[start + (i*4) ], 3) |
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49 + public.putByte(bytes[start + (i*4) + 1], 2) |
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50 + public.putByte(bytes[start + (i*4) + 2], 1) |
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51 + public.putByte(bytes[start + (i*4) + 3], 0); |
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52 end |
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53 return ints; |
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54 end |
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55 |
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56 -- |
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57 -- convert int array to byte array |
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58 -- |
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59 function public.intsToBytes(ints, output, outputOffset, n) |
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60 n = n or #ints; |
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61 for i = 0, n do |
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62 for j = 0,3 do |
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63 output[outputOffset + i*4 + (3 - j)] = public.getByte(ints[i], j); |
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64 end |
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65 end |
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66 return output; |
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67 end |
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68 |
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69 -- |
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70 -- convert bytes to hexString |
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71 -- |
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72 function private.bytesToHex(bytes) |
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73 local hexBytes = ""; |
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74 |
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75 for i,byte in ipairs(bytes) do |
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76 hexBytes = hexBytes .. string.format("%02x ", byte); |
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77 end |
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78 |
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79 return hexBytes; |
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80 end |
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81 |
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82 -- |
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83 -- convert data to hex string |
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84 -- |
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85 function public.toHexString(data) |
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86 local type = type(data); |
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87 if (type == "number") then |
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88 return string.format("%08x",data); |
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89 elseif (type == "table") then |
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90 return private.bytesToHex(data); |
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91 elseif (type == "string") then |
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92 local bytes = {string.byte(data, 1, #data)}; |
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93 |
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94 return private.bytesToHex(bytes); |
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95 else |
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96 return data; |
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97 end |
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98 end |
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99 |
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100 function public.padByteString(data) |
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101 local dataLength = #data; |
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102 |
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103 local random1 = math.random(0,255); |
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104 local random2 = math.random(0,255); |
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105 |
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106 local prefix = string.char(random1, |
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107 random2, |
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108 random1, |
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109 random2, |
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110 public.getByte(dataLength, 3), |
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111 public.getByte(dataLength, 2), |
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112 public.getByte(dataLength, 1), |
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113 public.getByte(dataLength, 0)); |
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114 |
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115 data = prefix .. data; |
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116 |
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117 local paddingLength = math.ceil(#data/16)*16 - #data; |
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118 local padding = ""; |
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119 for i=1,paddingLength do |
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120 padding = padding .. string.char(math.random(0,255)); |
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121 end |
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122 |
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123 return data .. padding; |
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124 end |
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125 |
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126 function private.properlyDecrypted(data) |
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127 local random = {string.byte(data,1,4)}; |
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128 |
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129 if (random[1] == random[3] and random[2] == random[4]) then |
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130 return true; |
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131 end |
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132 |
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133 return false; |
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134 end |
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135 |
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136 function public.unpadByteString(data) |
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137 if (not private.properlyDecrypted(data)) then |
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138 return nil; |
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139 end |
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140 |
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141 local dataLength = public.putByte(string.byte(data,5), 3) |
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142 + public.putByte(string.byte(data,6), 2) |
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143 + public.putByte(string.byte(data,7), 1) |
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144 + public.putByte(string.byte(data,8), 0); |
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145 |
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146 return string.sub(data,9,8+dataLength); |
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147 end |
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148 |
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149 function public.xorIV(data, iv) |
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150 for i = 1,16 do |
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151 data[i] = bit.bxor(data[i], iv[i]); |
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152 end |
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153 end |
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154 |
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155 return public; |