47 lines
1.8 KiB
C#
47 lines
1.8 KiB
C#
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using System.Collections.Generic;
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namespace Obfuz.EncryptionVM.Instructions
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{
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public class BitRotateInstruction : EncryptionInstructionBase
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{
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private readonly int _rotateBitNum;
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private readonly int _opKeyIndex;
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public BitRotateInstruction(int rotateBitNum, int opKeyIndex)
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{
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_rotateBitNum = rotateBitNum;
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_opKeyIndex = opKeyIndex;
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}
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public override int Encrypt(int value, int[] secretKey, int salt)
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{
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uint part1 = (uint)value << _rotateBitNum;
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uint part2 = (uint)value >> (32 - _rotateBitNum);
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return ((int)(part1 | part2) ^ secretKey[_opKeyIndex]) + salt;
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}
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public override int Decrypt(int value, int[] secretKey, int salt)
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{
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uint value2 = (uint)((value - salt) ^ secretKey[_opKeyIndex]);
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uint part1 = value2 >> _rotateBitNum;
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uint part2 = value2 << (32 - _rotateBitNum);
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return (int)(part1 | part2);
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}
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public override void GenerateEncryptCode(List<string> lines, string indent)
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{
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lines.Add(indent + $"uint part1 = (uint)value << {_rotateBitNum};");
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lines.Add(indent + $"uint part2 = (uint)value >> (32 - {_rotateBitNum});");
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lines.Add(indent + $"value = ((int)(part1 | part2) ^ _secretKey[{_opKeyIndex}]) + salt;");
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}
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public override void GenerateDecryptCode(List<string> lines, string indent)
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{
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lines.Add(indent + $"uint value2 = (uint)((value - salt) ^ _secretKey[{_opKeyIndex}]);");
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lines.Add(indent + $"uint part1 = value2 >> {_rotateBitNum};");
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lines.Add(indent + $"uint part2 = value2 << (32 - {_rotateBitNum});");
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lines.Add(indent + $"value = (int)(part1 | part2);");
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}
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}
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}
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