// verified
private static ListOfDiffPairs UndoLastRound(ListOfDiffPairs diffPairs, UInt32 subKey)
{
var result = new ListOfDiffPairs();
for (var i = 0; i < numberOfPlain; ++i)
{
UInt32 firstCipherLeft = Feal4Helper.GetLeftHalf(diffPairs[i].Item1.Cipher);
UInt32 firstCipherRight = Feal4Helper.GetRightHalf(diffPairs[i].Item1.Cipher);
UInt32 secondCipherLeft = Feal4Helper.GetLeftHalf(diffPairs[i].Item2.Cipher);
UInt32 secondCipherRight = Feal4Helper.GetRightHalf(diffPairs[i].Item2.Cipher);
firstCipherLeft = firstCipherRight;
secondCipherLeft = secondCipherRight;
firstCipherRight = Feal4Helper.Fbox(firstCipherLeft ^ subKey) ^ (Feal4Helper.GetLeftHalf(diffPairs[i].Item1.Cipher));
secondCipherRight = Feal4Helper.Fbox(secondCipherLeft ^ subKey) ^ (Feal4Helper.GetLeftHalf(diffPairs[i].Item2.Cipher));
var firstObj = new PlainCipherPair <UInt64>(diffPairs[i].Item1.Plain,
Feal4Helper.Combine32BitHalfs(firstCipherLeft, firstCipherRight));
var secondObj = new PlainCipherPair <UInt64>(diffPairs[i].Item2.Plain,
Feal4Helper.Combine32BitHalfs(secondCipherLeft, secondCipherRight));
result.Add(Tuple.Create(firstObj, secondObj));
}
return(result);
}
public void TestCombine32BitHalfs()
{
const UInt32 leftHalf = 0b11010101111111110110101000001000;
const UInt32 rightHalf = 0b00010000010101101111111110101011;
const UInt64 expectedResult = 0b1101010111111111011010100000100000010000010101101111111110101011;
Feal4Helper.Combine32BitHalfs(leftHalf, rightHalf).Should().Be(expectedResult);
}
public void TestRotateLeft()
{
const byte value = (byte)(0b10111101);
const byte expectedRotated = (byte)(0b11110110);
var actualRotated = Feal4Helper.Rotl2(value);
actualRotated.Should().Be(expectedRotated);
}
public void TestCombineBytes()
{
const byte zeroByte = 0b00001000;
const byte firstByte = 0b01101010;
const byte secondByte = 0b11111111;
const byte thirdByte = 0b11010101;
Feal4Helper.CombineBytes(thirdByte, secondByte, firstByte, zeroByte).Should()
.Be(0b11010101111111110110101000001000);
}
public void TestGetNthByte()
{
const UInt32 value = 0b11010101111111110110101000001000;
const byte expectedZeroByte = 0b00001000;
const byte expectedFirstByte = 0b01101010;
const byte expectedSecondByte = 0b11111111;
const byte expectedThirdByte = 0b11010101;
Feal4Helper.GetNthByte(value, 0).Should().Be(expectedZeroByte);
Feal4Helper.GetNthByte(value, 1).Should().Be(expectedFirstByte);
Feal4Helper.GetNthByte(value, 2).Should().Be(expectedSecondByte);
Feal4Helper.GetNthByte(value, 3).Should().Be(expectedThirdByte);
}
// verified
private static int GetScore(UInt32 outDiff, ListOfDiffPairs chosenPlaintexts,
UInt32 fakeK32)
{
var score = 0;
for (var i = 0; i < numberOfPlain; ++i)
{
var cipherLeft = Feal4Helper.GetLeftHalf(chosenPlaintexts[i].Item1.Cipher) ^
Feal4Helper.GetLeftHalf(chosenPlaintexts[i].Item2.Cipher);
var cipherRight = Feal4Helper.GetRightHalf(chosenPlaintexts[i].Item1.Cipher) ^
Feal4Helper.GetRightHalf(chosenPlaintexts[i].Item2.Cipher);
var y = cipherRight;
var z = cipherLeft ^ outDiff;
var firstFakeLeft =
Feal4Helper.GetLeftHalf(chosenPlaintexts[i].Item1.Cipher);
var firstFakeRight =
Feal4Helper.GetRightHalf(chosenPlaintexts[i].Item1.Cipher);
var secondFakeLeft =
Feal4Helper.GetLeftHalf(chosenPlaintexts[i].Item2.Cipher);
var secondFakeRight =
Feal4Helper.GetRightHalf(chosenPlaintexts[i].Item2.Cipher);
var y0 = firstFakeRight;
var y1 = secondFakeRight;
var fakeInput0 = y0 ^ fakeK32;
var fakeInput1 = y1 ^ fakeK32;
var fakeOut0 = Feal4Helper.Fbox(fakeInput0);
var fakeOut1 = Feal4Helper.Fbox(fakeInput1);
var fakeDiff = fakeOut0 ^ fakeOut1;
if (fakeDiff == z)
{
++score;
}
else
{
break;
}
}
return(score);
}
// verified
private ListOfDiffPairs UndoFinalOperation(ListOfDiffPairs data)
{
var result = new ListOfDiffPairs();
foreach (var item in data)
{
var firstLeftCipher = Feal4Helper.GetLeftHalf(item.Item1.Cipher);
var firstRightCipher = Feal4Helper.GetRightHalf(item.Item1.Cipher) ^ firstLeftCipher;
var secondLeftCipher = Feal4Helper.GetLeftHalf(item.Item2.Cipher);
var secondRightCipher = Feal4Helper.GetRightHalf(item.Item2.Cipher) ^ secondLeftCipher;
var firstRecombined = Feal4Helper.Combine32BitHalfs(firstLeftCipher, firstRightCipher);
var secondRecombined = Feal4Helper.Combine32BitHalfs(secondLeftCipher, secondRightCipher);
var firstObj = new PlainCipherPair64(item.Item1.Plain, firstRecombined);
var secondObj = new PlainCipherPair64(item.Item2.Plain, secondRecombined);
result.Add(Tuple.Create(firstObj, secondObj));
}
return(result);
}
public void TestGetRightHalf()
{
const UInt64 value = 0b1101010111111111011010100000100000010000010101101111111110101011;
Feal4Helper.GetRightHalf(value).Should().Be(0b00010000010101101111111110101011);
}
public UInt32[] Analyze()
{
var commonStopWatch = Stopwatch.StartNew();
Console.WriteLine("CRACKING ROUND 4");
var fourthRoundStopWatch = Stopwatch.StartNew();
var fourthRoundChosenPlaintexts = GetChosenPlaintexts(inputDiff1);
var fourthRoundUndoneFinalOperation = UndoFinalOperation(fourthRoundChosenPlaintexts);
//for (var i = 0; i < fourthRoundUndoneFinalOperation.Count; ++i)
// Console.WriteLine(fourthRoundUndoneFinalOperation[i].Item1.Cipher);
var fourthRoundSubKey = CrackLastRound(outputDiff, fourthRoundUndoneFinalOperation);
Console.WriteLine($"4-th round cracking time: {fourthRoundStopWatch.Elapsed}");
Console.WriteLine($"4-th round subkey: {fourthRoundSubKey}");
Console.WriteLine("CRACKING ROUND 3");
var thirdRoundStopWatch = Stopwatch.StartNew();
var thirdRoundChosenPlaintexts = GetChosenPlaintexts(inputDiff2);
var thirdRoundUndoneFinalOperation = UndoFinalOperation(thirdRoundChosenPlaintexts);
var thirdRoundUndoneLastRound = UndoLastRound(thirdRoundUndoneFinalOperation, fourthRoundSubKey);
var thirdRoundSubKey = CrackLastRound(outputDiff, thirdRoundUndoneLastRound);
Console.WriteLine($"3-th round cracking time: {thirdRoundStopWatch.Elapsed}");
Console.WriteLine("CRACKING ROUND 2");
var secondRoundStopWatch = Stopwatch.StartNew();
var secondRoundChosenPlaintexts = GetChosenPlaintexts(inputDiff3);
var secondRoundUndoneFinalOperation = UndoFinalOperation(secondRoundChosenPlaintexts);
var secondRoundUndoneLastRound = UndoLastRound(secondRoundUndoneFinalOperation, fourthRoundSubKey);
var secondRoundUndonePrevLastRound = UndoLastRound(secondRoundUndoneLastRound, thirdRoundSubKey);
var secondRoundSubKey = CrackLastRound(outputDiff, secondRoundUndonePrevLastRound);
Console.WriteLine($"2-th round cracking time: {secondRoundStopWatch.Elapsed}");
Console.WriteLine("CRACKING ROUND 1");
var firstRoundStopWatch = Stopwatch.StartNew();
var firstRoundUndoLastRound = UndoLastRound(secondRoundUndonePrevLastRound, secondRoundSubKey);
UInt32 crackedSubKey0 = 0;
UInt32 crackedSubKey4 = 0;
UInt32 crackedSubKey5 = 0;
for (UInt64 guessK0 = 0; guessK0 < (UInt64)UInt32.MaxValue; ++guessK0)
{
var guessK032 = (UInt32)guessK0;
UInt32 guessK4 = 0;
UInt32 guessK5 = 0;
for (var i = 0; i < numberOfPlain; ++i)
{
var firstPlainLeft = Feal4Helper.GetLeftHalf(
firstRoundUndoLastRound[i].Item1.Plain);
var firstPlainRight = Feal4Helper.GetRightHalf(
firstRoundUndoLastRound[i].Item1.Plain);
var firstCipherLeft = Feal4Helper.GetLeftHalf(
firstRoundUndoLastRound[i].Item1.Cipher);
var firstCipherRight = Feal4Helper.GetRightHalf(
firstRoundUndoLastRound[i].Item1.Cipher);
var tempY0 =
Feal4Helper.Fbox(firstCipherRight ^ guessK032) ^ firstCipherLeft;
if (guessK4 == 0)
{
guessK4 = tempY0 ^ firstPlainLeft;
guessK5 = tempY0 ^ firstCipherRight ^ firstPlainRight;
}
else if (((tempY0 ^ firstPlainLeft) != guessK4) ||
((tempY0 ^ firstCipherRight ^ firstPlainRight) != guessK5))
{
guessK4 = 0;
guessK5 = 0;
break;
}
}
if (guessK4 != 0)
{
crackedSubKey0 = guessK032;
crackedSubKey4 = guessK4;
crackedSubKey5 = guessK5;
break;
}
}
Console.WriteLine($"1-th round cracking time: {firstRoundStopWatch.Elapsed}");
Console.WriteLine($"Overall elapsed time: {commonStopWatch.Elapsed}");
if (subKeys[0] == crackedSubKey0)
{
Console.WriteLine("0-th subkey GOOD");
}
if (subKeys[1] == secondRoundSubKey)
{
Console.WriteLine("1-th subkey GOOD");
}
if (subKeys[2] == thirdRoundSubKey)
{
Console.WriteLine("2-th subkey GOOD");
}
if (subKeys[3] == fourthRoundSubKey)
{
Console.WriteLine("3-th subkey GOOD");
}
if (subKeys[4] == crackedSubKey4)
{
Console.WriteLine("4-th subkey GOOD");
}
if (subKeys[5] == crackedSubKey5)
{
Console.WriteLine("5-th subkey GOOD");
}
return(new[]
{
crackedSubKey0, secondRoundSubKey, thirdRoundSubKey,
fourthRoundSubKey, crackedSubKey4, crackedSubKey5
});
}