public void SubWord(List <FiniteField> word)
{
for (int i = 0; i < word.Count; i++)
{
word[i] = FiniteField.SBox(word[i]);
}
}
public static FiniteField operator ~(FiniteField a)
{
if (a == new FiniteField())
{
return(new FiniteField());
}
FiniteField t = new FiniteField();
FiniteField newt = new FiniteField("00000001");
FiniteField r = IrreduciblePolynomial;
FiniteField newr = a;
while (newr != new FiniteField())
{
FiniteField quotient = r / newr;
FiniteField prov2 = newr;
newr = r + quotient * prov2;
r = prov2;
FiniteField prov = newt;
newt = t + quotient * prov;
t = prov;
}
return(t);
}
public static FiniteField operator -(FiniteField a, FiniteField b)
{
if (a < b)
{
FiniteField c = new FiniteField(a.Count);
c = a;
a = b;
b = c;
}
FiniteField temp = a.Clone();
int aStart = a.FirstNonZero;
int bStart = b.FirstNonZero;
if (b == new FiniteField())
{
return(a);
}
for (int i = 0; i < b.Count - bStart; i++)
{
temp[i + aStart] = Convert.ToByte(a[i + aStart] ^ b[i + bStart]);
}
return(temp);
}
public void RotWord(List <FiniteField> word)
{
FiniteField temp = word[0];
for (int i = 0; i < word.Count - 1; i++)
{
word[i] = word[i + 1];
}
word[word.Count - 1] = temp;
}
public static FiniteField operator %(FiniteField a, FiniteField b)
{
FiniteField reminder = a.Clone();
while (reminder >= b)
{
reminder -= b;
}
return(reminder);
}
public static FiniteField operator *(FiniteField a, FiniteField b)
{
FiniteField product = new FiniteField(a.Count + b.Count - 1);
for (int i = 0; i < a.Count; i++)
{
for (int j = 0; j < b.Count; j++)
{
product[i + j] = Convert.ToByte(a[i] & b[j] ^ product[i + j]);
}
}
product.Cut();
return(product);
}
public static FiniteField operator <<(FiniteField a, int count)
{
FiniteField temp = new FiniteField(a.Count);
int index = temp.Count - count;
for (int i = 0; i < a.Count; i++)
{
temp[index] = a[i];
index++;
index %= a.Count;
}
return(temp);
}
public StateMatrix InvSubBytes(StateMatrix stateMatrix)
{
StateMatrix subbedMatrix = new StateMatrix();
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
subbedMatrix[j, i] = FiniteField.InvSBox(stateMatrix[j, i]);
}
}
return(subbedMatrix);
}
public void Rcon(ref FiniteField roundConstant, int round)
{
if (round == 1)
{
return;
}
else if (roundConstant < new FiniteField("10000000"))
{
roundConstant *= new FiniteField("00000010");
}
else
{
roundConstant = roundConstant * new FiniteField("00000010") + new FiniteField("100011011");
}
}
public static FiniteField operator /(FiniteField a, FiniteField b)
{
FiniteField quotient = new FiniteField(a.Count);
FiniteField temp = a.Clone();
while (temp.Count - temp.FirstNonZero >= b.Count - b.FirstNonZero)
{
int aFirst = temp.Count - temp.FirstNonZero;
int bFirst = b.Count - b.FirstNonZero;
int shift = Math.Abs(aFirst - bFirst);
quotient[quotient.Count - 1 - shift] = 1;
temp -= b;
}
return(quotient);
}
public StateMatrix InvMixColumns(StateMatrix stateMatrix)
{
StateMatrix mixedMatrix = new StateMatrix();
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
mixedMatrix[i, j] = new FiniteField();
for (int k = 0; k < 4; k++)
{
mixedMatrix[i, j] += stateMatrix[k, j] * StateMatrix.InvC[i, k];
}
}
}
return(mixedMatrix);
}
public void Cut()
{
while (Coefficients.Length - FirstNonZero >= IrreduciblePolynomial.Count)
{
FiniteField reminder = this - IrreduciblePolynomial;
Coefficients = reminder.Coefficients;
}
byte[] reduced = new byte[8];
int length = Coefficients.Length - 8;
for (int i = 0; i < 8; i++)
{
reduced[i] = Coefficients[length + i];
}
Coefficients = reduced;
}
public static FiniteField operator +(FiniteField a, FiniteField b)
{
FiniteField temp;
int shift;
if (a.Count < b.Count)
{
temp = new FiniteField(b.Count);
shift = b.Count - a.Count;
for (int i = 0; i < shift; i++)
{
temp[i] = b[i];
}
for (int i = 0; i < a.Count; i++)
{
temp[i + shift] = Convert.ToByte(a[i] ^ b[i + shift]);
}
}
else if (b.Count < a.Count)
{
temp = new FiniteField(a.Count);
shift = a.Count - b.Count;
for (int i = 0; i < shift; i++)
{
temp[i] = a[i];
}
for (int i = 0; i < b.Count; i++)
{
temp[i + shift] = Convert.ToByte(a[i + shift] ^ b[i]);
}
}
else
{
temp = new FiniteField(a.Count);
for (int i = 0; i < a.Count; i++)
{
temp[i] = Convert.ToByte(a[i] ^ b[i]);
}
}
temp.Cut();
return(temp);
}
static int Compare(FiniteField a, FiniteField b)
{
int indexA = 0;
int indexB = 0;
if (a.Count > b.Count)
{
while (indexA < a.Count - b.Count)
{
if (a[indexA] == 1)
{
return(1);
}
indexA++;
}
}
if (b.Count > a.Count)
{
while (indexB < b.Count - a.Count)
{
if (b[indexB] == 1)
{
return(-1);
}
indexB++;
}
}
for (int i = 0; i < Math.Min(a.Count, b.Count); i++)
{
if (a[i + indexA] < b[i + indexB])
{
return(-1);
}
else if (a[i + indexA] > b[i + indexB])
{
return(1);
}
}
return(0);
}
public void GenerateKey()
{
RoundKeys = new List <StateMatrix>();
StateMatrix roundKey = new StateMatrix();
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
roundKey[j, i] = new FiniteField(Convert.ToString(EncryptionKey[i * 4 + j], 2).PadLeft(8, '0'));
}
}
FiniteField roundConstant = new FiniteField("00000001");
RoundKeys.Add(roundKey);
for (int round = 1; round <= 10; round++)
{
roundKey = new StateMatrix();
List <FiniteField> word = new List <FiniteField>();
for (int i = 0; i < 4; i++)
{
word.Add(RoundKeys[round - 1][i, 3]);
}
RotWord(word);
SubWord(word);
Rcon(ref roundConstant, round);
word[0] = word[0] + roundConstant;
for (int i = 0; i < 4; i++)
{
roundKey[i, 0] = RoundKeys[round - 1][i, 0] + word[i];
}
for (int i = 1; i < 4; i++)
{
for (int j = 0; j < 4; j++)
{
roundKey[j, i] = RoundKeys[round - 1][j, i] + roundKey[j, i - 1];
}
}
RoundKeys.Add(roundKey);
}
}
public static FiniteField SBox(FiniteField b)
{
FiniteField s = ~b;
return(s + (s << 1) + (s << 2) + (s << 3) + (s << 4) + C);
}
public static FiniteField InvSBox(FiniteField s)
{
FiniteField b = (s << 1) + (s << 3) + (s << 6) + InvC;
return(~b);
}
