static void AttackLastRound()
{
Encryption encryption = new Encryption();
Analysis analysis = new Analysis();
Console.WriteLine("Current keys: " + encryption.PrintKeys());
//analysis the sbox
List <Differential> diffList = analysis.CountDifferentialsSingleSBox();
bool[] attackSBox = new bool[] { true };
//Check the attack new
CipherThreeDifferentialKeyRecoveryAttack keyRecoveryConfiguration = new CipherThreeDifferentialKeyRecoveryAttack();
SearchPolicy curSearchPolicy = SearchPolicy.FirstBestCharacteristicDepthSearch;
AbortingPolicy curAbortingPolicy = AbortingPolicy.Threshold;
//attack round 3
DifferentialAttackRoundConfiguration configRound3SBox1 = analysis.GenerateConfigurationAttack(3, attackSBox, curAbortingPolicy, curSearchPolicy, diffList, keyRecoveryConfiguration, encryption);
DifferentialAttackRoundResult resultRound3SBox1 = analysis.RecoverKeyInformation(keyRecoveryConfiguration, configRound3SBox1, encryption);
keyRecoveryConfiguration.RoundConfigurations.Add(configRound3SBox1);
keyRecoveryConfiguration.RoundResults.Add(resultRound3SBox1);
//Result
keyRecoveryConfiguration.Subkey3 = resultRound3SBox1.PossibleKey;
keyRecoveryConfiguration.RecoveredSubkey3 = true;
Console.WriteLine(keyRecoveryConfiguration.printRecoveredSubkeyBits());
}
public int PartialDecrypt(DifferentialKeyRecoveryAttack attack, int block)
{
CipherThreeDifferentialKeyRecoveryAttack cipherThreeAttack = attack as CipherThreeDifferentialKeyRecoveryAttack;
int result = block;
if (cipherThreeAttack != null && cipherThreeAttack.RecoveredSubkey3)
{
result = DecryptSingleRound(result, cipherThreeAttack.Subkey3, false, true);
}
if (cipherThreeAttack != null && cipherThreeAttack.RecoveredSubkey2)
{
result = DecryptSingleRound(result, cipherThreeAttack.Subkey2, true, false);
}
if (cipherThreeAttack != null && cipherThreeAttack.RecoveredSubkey1)
{
result = DecryptSingleRound(result, cipherThreeAttack.Subkey1, false, false);
}
return(result);
}
public List <Pair> FilterPairs(DifferentialAttackRoundConfiguration roundConfig, List <Differential> diffListOfSBox,
DifferentialKeyRecoveryAttack attack, IEncryption encryption, int expectedDifferential)
{
//cast to use the object
CipherThreeDifferentialKeyRecoveryAttack cipherFourAttack = attack as CipherThreeDifferentialKeyRecoveryAttack;
if (cipherFourAttack == null)
{
throw new ArgumentNullException(nameof(attack));
}
//contains the filtered pairs
List <Pair> resultList = new List <Pair>();
List <int>[] arrayOfPossibleDifferentialsForSBoxes = new List <int> [CipherThreeConfiguration.SBOXNUM];
int[] arrayOfExpectedInputDifferentialsForSBoxes = new int[CipherThreeConfiguration.SBOXNUM];
for (int i = 0; i < CipherThreeConfiguration.SBOXNUM; i++)
{
arrayOfPossibleDifferentialsForSBoxes[i] = new List <int>();
arrayOfExpectedInputDifferentialsForSBoxes[i] = expectedDifferential;
if (arrayOfExpectedInputDifferentialsForSBoxes[i] == 0)
{
arrayOfPossibleDifferentialsForSBoxes[i].Add(0);
}
}
//iterate over the differentials
foreach (var curDiff in diffListOfSBox)
{
//Skip 0 InputDiff / OutputDiff
if (curDiff.InputDifferential == 0)
{
continue;
}
for (int i = 0; i < CipherThreeConfiguration.SBOXNUM; i++)
{
if (arrayOfExpectedInputDifferentialsForSBoxes[i] == curDiff.InputDifferential)
{
arrayOfPossibleDifferentialsForSBoxes[i].Add(curDiff.OutputDifferential);
}
}
}
//check all pairs for the conditions
foreach (var curPair in roundConfig.UnfilteredPairList)
{
int cipherTextLeftMember = encryption.EncryptBlock(curPair.LeftMember);
int cipherTextRightMember = encryption.EncryptBlock(curPair.RightMember);
cipherTextLeftMember = PartialDecrypt(attack, cipherTextLeftMember);
cipherTextRightMember = PartialDecrypt(attack, cipherTextRightMember);
int diffOfCipherText = (cipherTextLeftMember ^ cipherTextRightMember);
int[] diffOfCipherTextSBoxes = new int[CipherThreeConfiguration.SBOXNUM];
bool[] conditionsOfSBoxes = new bool[CipherThreeConfiguration.SBOXNUM];
for (int i = 0; i < CipherThreeConfiguration.SBOXNUM; i++)
{
diffOfCipherTextSBoxes[i] = diffOfCipherText;
conditionsOfSBoxes[i] = false;
}
for (int i = 0; i < CipherThreeConfiguration.SBOXNUM; i++)
{
foreach (var possibleOutputDiff in arrayOfPossibleDifferentialsForSBoxes[i])
{
if (possibleOutputDiff == diffOfCipherTextSBoxes[i])
{
conditionsOfSBoxes[i] = true;
}
}
}
bool satisfied = true;
for (int i = 0; i < CipherThreeConfiguration.SBOXNUM; i++)
{
if (conditionsOfSBoxes[i] == false)
{
satisfied = false;
}
}
if (satisfied)
{
resultList.Add(curPair);
}
}
return(resultList);
}
