public static bool RsaOTDecrypt(ref byte[] buffer, int position, int length)
{
if (length - position != 128)
return false;
byte[] temp = new byte[128];
Array.Copy(buffer, position, temp, 0, 128);
BigInteger input = new BigInteger(temp);
BigInteger output;
BigInteger m1 = input.modPow(otServerDP, otServerP);
// m2 = c^dq mod q
BigInteger m2 = input.modPow(otServerDQ, otServerQ);
BigInteger h;
if (m2 > m1)
{
// thanks to benm!
h = otServerP - ((m2 - m1) * otServerInverseQ % otServerP);
output = m2 + otServerQ * h;
}
else
{
// h = (m1 - m2) * qInv mod p
h = (m1 - m2) * otServerInverseQ % otServerP;
// m = m2 + q * h;
output = m2 + otServerQ * h;
}
Array.Copy(GetPaddedValue(output), 0, buffer, position, 128);
return true;
}
public static bool RsaEncrypt(BigInteger e, BigInteger m, ref byte[] buffer, int position)
{
byte[] temp = new byte[128];
Array.Copy(buffer, position, temp, 0, 128);
BigInteger input = new BigInteger(temp);
BigInteger output = input.modPow(e, m);
// it's sometimes possible for the results to be a byte short
// and this can break some software so we 0x00 pad the result
Array.Copy(GetPaddedValue(output), 0, buffer, position, 128);
return true;
}
//***********************************************************************
// Overloading of modulus operator
//***********************************************************************
public static BigInteger operator %(BigInteger bi1, BigInteger bi2)
{
BigInteger quotient = new BigInteger();
BigInteger remainder = new BigInteger(bi1);
int lastPos = maxLength - 1;
bool dividendNeg = false;
if ((bi1.data[lastPos] & 0x80000000) != 0) // bi1 negative
{
bi1 = -bi1;
dividendNeg = true;
}
if ((bi2.data[lastPos] & 0x80000000) != 0) // bi2 negative
bi2 = -bi2;
if (bi1 < bi2)
{
return remainder;
}
else
{
if (bi2.dataLength == 1)
singleByteDivide(bi1, bi2, quotient, remainder);
else
multiByteDivide(bi1, bi2, quotient, remainder);
if (dividendNeg)
return -remainder;
return remainder;
}
}
//***********************************************************************
// Private function that supports the division of two numbers with
// a divisor that has more than 1 digit.
//
// Algorithm taken from [1]
//***********************************************************************
private static void multiByteDivide(BigInteger bi1, BigInteger bi2,
BigInteger outQuotient, BigInteger outRemainder)
{
uint[] result = new uint[maxLength];
int remainderLen = bi1.dataLength + 1;
uint[] remainder = new uint[remainderLen];
uint mask = 0x80000000;
uint val = bi2.data[bi2.dataLength - 1];
int shift = 0, resultPos = 0;
while (mask != 0 && (val & mask) == 0)
{
shift++; mask >>= 1;
}
//Console.WriteLine("shift = {0}", shift);
//Console.WriteLine("Before bi1 Len = {0}, bi2 Len = {1}", bi1.dataLength, bi2.dataLength);
for (int i = 0; i < bi1.dataLength; i++)
remainder[i] = bi1.data[i];
shiftLeft(remainder, shift);
bi2 = bi2 << shift;
/*
Console.WriteLine("bi1 Len = {0}, bi2 Len = {1}", bi1.dataLength, bi2.dataLength);
Console.WriteLine("dividend = " + bi1 + "\ndivisor = " + bi2);
for(int q = remainderLen - 1; q >= 0; q--)
Console.Write("{0:x2}", remainder[q]);
Console.WriteLine();
*/
int j = remainderLen - bi2.dataLength;
int pos = remainderLen - 1;
ulong firstDivisorByte = bi2.data[bi2.dataLength - 1];
ulong secondDivisorByte = bi2.data[bi2.dataLength - 2];
int divisorLen = bi2.dataLength + 1;
uint[] dividendPart = new uint[divisorLen];
while (j > 0)
{
ulong dividend = ((ulong)remainder[pos] << 32) + (ulong)remainder[pos - 1];
//Console.WriteLine("dividend = {0}", dividend);
ulong q_hat = dividend / firstDivisorByte;
ulong r_hat = dividend % firstDivisorByte;
//Console.WriteLine("q_hat = {0:X}, r_hat = {1:X}", q_hat, r_hat);
bool done = false;
while (!done)
{
done = true;
if (q_hat == 0x100000000 ||
(q_hat * secondDivisorByte) > ((r_hat << 32) + remainder[pos - 2]))
{
q_hat--;
r_hat += firstDivisorByte;
if (r_hat < 0x100000000)
done = false;
}
}
for (int h = 0; h < divisorLen; h++)
dividendPart[h] = remainder[pos - h];
BigInteger kk = new BigInteger(dividendPart);
BigInteger ss = bi2 * (long)q_hat;
//Console.WriteLine("ss before = " + ss);
while (ss > kk)
{
q_hat--;
ss -= bi2;
//Console.WriteLine(ss);
}
BigInteger yy = kk - ss;
//Console.WriteLine("ss = " + ss);
//Console.WriteLine("kk = " + kk);
//Console.WriteLine("yy = " + yy);
for (int h = 0; h < divisorLen; h++)
remainder[pos - h] = yy.data[bi2.dataLength - h];
/*
Console.WriteLine("dividend = ");
for(int q = remainderLen - 1; q >= 0; q--)
Console.Write("{0:x2}", remainder[q]);
Console.WriteLine("\n************ q_hat = {0:X}\n", q_hat);
*/
result[resultPos++] = (uint)q_hat;
pos--;
j--;
}
outQuotient.dataLength = resultPos;
int y = 0;
for (int x = outQuotient.dataLength - 1; x >= 0; x--, y++)
outQuotient.data[y] = result[x];
for (; y < maxLength; y++)
outQuotient.data[y] = 0;
while (outQuotient.dataLength > 1 && outQuotient.data[outQuotient.dataLength - 1] == 0)
outQuotient.dataLength--;
if (outQuotient.dataLength == 0)
outQuotient.dataLength = 1;
outRemainder.dataLength = shiftRight(remainder, shift);
for (y = 0; y < outRemainder.dataLength; y++)
outRemainder.data[y] = remainder[y];
for (; y < maxLength; y++)
outRemainder.data[y] = 0;
}
//***********************************************************************
// Overloading of the NOT operator (1's complement)
//***********************************************************************
public static BigInteger operator ~(BigInteger bi1)
{
BigInteger result = new BigInteger(bi1);
for (int i = 0; i < maxLength; i++)
result.data[i] = (uint)(~(bi1.data[i]));
result.dataLength = maxLength;
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
return result;
}
//***********************************************************************
// Overloading of unary << operators
//***********************************************************************
public static BigInteger operator <<(BigInteger bi1, int shiftVal)
{
BigInteger result = new BigInteger(bi1);
result.dataLength = shiftLeft(result.data, shiftVal);
return result;
}
//***********************************************************************
// Overloading of the unary -- operator
//***********************************************************************
public static BigInteger operator --(BigInteger bi1)
{
BigInteger result = new BigInteger(bi1);
long val;
bool carryIn = true;
int index = 0;
while (carryIn && index < maxLength)
{
val = (long)(result.data[index]);
val--;
result.data[index] = (uint)(val & 0xFFFFFFFF);
if (val >= 0)
carryIn = false;
index++;
}
if (index > result.dataLength)
result.dataLength = index;
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
// overflow check
int lastPos = maxLength - 1;
// overflow if initial value was -ve but -- caused a sign
// change to positive.
if ((bi1.data[lastPos] & 0x80000000) != 0 &&
(result.data[lastPos] & 0x80000000) != (bi1.data[lastPos] & 0x80000000))
{
throw (new ArithmeticException("Underflow in --."));
}
return result;
}
//***********************************************************************
// Overloading of the unary ++ operator
//***********************************************************************
public static BigInteger operator ++(BigInteger bi1)
{
BigInteger result = new BigInteger(bi1);
long val, carry = 1;
int index = 0;
while (carry != 0 && index < maxLength)
{
val = (long)(result.data[index]);
val++;
result.data[index] = (uint)(val & 0xFFFFFFFF);
carry = val >> 32;
index++;
}
if (index > result.dataLength)
result.dataLength = index;
else
{
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
}
// overflow check
int lastPos = maxLength - 1;
// overflow if initial value was +ve but ++ caused a sign
// change to negative.
if ((bi1.data[lastPos] & 0x80000000) == 0 &&
(result.data[lastPos] & 0x80000000) != (bi1.data[lastPos] & 0x80000000))
{
throw (new ArithmeticException("Overflow in ++."));
}
return result;
}
//***********************************************************************
// Modulo Exponentiation
//***********************************************************************
public BigInteger modPow(BigInteger exp, BigInteger n)
{
if ((exp.data[maxLength - 1] & 0x80000000) != 0)
throw (new ArithmeticException("Positive exponents only."));
BigInteger resultNum = 1;
BigInteger tempNum;
bool thisNegative = false;
if ((this.data[maxLength - 1] & 0x80000000) != 0) // negative this
{
tempNum = -this % n;
thisNegative = true;
}
else
tempNum = this % n; // ensures (tempNum * tempNum) < b^(2k)
if ((n.data[maxLength - 1] & 0x80000000) != 0) // negative n
n = -n;
// calculate constant = b^(2k) / m
BigInteger constant = new BigInteger();
int i = n.dataLength << 1;
constant.data[i] = 0x00000001;
constant.dataLength = i + 1;
constant = constant / n;
int totalBits = exp.bitCount();
int count = 0;
// perform squaring and multiply exponentiation
for (int pos = 0; pos < exp.dataLength; pos++)
{
uint mask = 0x01;
//Console.WriteLine("pos = " + pos);
for (int index = 0; index < 32; index++)
{
if ((exp.data[pos] & mask) != 0)
resultNum = BarrettReduction(resultNum * tempNum, n, constant);
mask <<= 1;
tempNum = BarrettReduction(tempNum * tempNum, n, constant);
if (tempNum.dataLength == 1 && tempNum.data[0] == 1)
{
if (thisNegative && (exp.data[0] & 0x1) != 0) //odd exp
return -resultNum;
return resultNum;
}
count++;
if (count == totalBits)
break;
}
}
if (thisNegative && (exp.data[0] & 0x1) != 0) //odd exp
return -resultNum;
return resultNum;
}
//***********************************************************************
// Returns a string representing the BigInteger in sign-and-magnitude
// format in the specified radix.
//
// Example
// -------
// If the value of BigInteger is -255 in base 10, then
// ToString(16) returns "-FF"
//
//***********************************************************************
public string ToString(int radix)
{
if (radix < 2 || radix > 36)
throw (new ArgumentException("Radix must be >= 2 and <= 36"));
string charSet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string result = "";
BigInteger a = this;
bool negative = false;
if ((a.data[maxLength - 1] & 0x80000000) != 0)
{
negative = true;
try
{
a = -a;
}
catch (Exception) { }
}
BigInteger quotient = new BigInteger();
BigInteger remainder = new BigInteger();
BigInteger biRadix = new BigInteger(radix);
if (a.dataLength == 1 && a.data[0] == 0)
result = "0";
else
{
while (a.dataLength > 1 || (a.dataLength == 1 && a.data[0] != 0))
{
singleByteDivide(a, biRadix, quotient, remainder);
if (remainder.data[0] < 10)
result = remainder.data[0] + result;
else
result = charSet[(int)remainder.data[0] - 10] + result;
a = quotient;
}
if (negative)
result = "-" + result;
}
return result;
}
//***********************************************************************
// Returns min(this, bi)
//***********************************************************************
public BigInteger min(BigInteger bi)
{
if (this < bi)
return (new BigInteger(this));
else
return (new BigInteger(bi));
}
//***********************************************************************
// Returns max(this, bi)
//***********************************************************************
public BigInteger max(BigInteger bi)
{
if (this > bi)
return (new BigInteger(this));
else
return (new BigInteger(bi));
}
//***********************************************************************
// Overloading of bitwise XOR operator
//***********************************************************************
public static BigInteger operator ^(BigInteger bi1, BigInteger bi2)
{
BigInteger result = new BigInteger();
int len = (bi1.dataLength > bi2.dataLength) ? bi1.dataLength : bi2.dataLength;
for (int i = 0; i < len; i++)
{
uint sum = (uint)(bi1.data[i] ^ bi2.data[i]);
result.data[i] = sum;
}
result.dataLength = maxLength;
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
return result;
}
//***********************************************************************
// Constructor (Default value provided by BigInteger)
//***********************************************************************
public BigInteger(BigInteger bi)
{
data = new uint[maxLength];
dataLength = bi.dataLength;
for (int i = 0; i < dataLength; i++)
data[i] = bi.data[i];
}
//***********************************************************************
// Performs the calculation of the kth term in the Lucas Sequence.
// For details of the algorithm, see reference [9].
//
// k must be odd. i.e LSB == 1
//***********************************************************************
private static BigInteger[] LucasSequenceHelper(BigInteger P, BigInteger Q,
BigInteger k, BigInteger n,
BigInteger constant, int s)
{
BigInteger[] result = new BigInteger[3];
if ((k.data[0] & 0x00000001) == 0)
throw (new ArgumentException("Argument k must be odd."));
int numbits = k.bitCount();
uint mask = (uint)0x1 << ((numbits & 0x1F) - 1);
// v = v0, v1 = v1, u1 = u1, Q_k = Q^0
BigInteger v = 2 % n, Q_k = 1 % n,
v1 = P % n, u1 = Q_k;
bool flag = true;
for (int i = k.dataLength - 1; i >= 0; i--) // iterate on the binary expansion of k
{
//Console.WriteLine("round");
while (mask != 0)
{
if (i == 0 && mask == 0x00000001) // last bit
break;
if ((k.data[i] & mask) != 0) // bit is set
{
// index doubling with addition
u1 = (u1 * v1) % n;
v = ((v * v1) - (P * Q_k)) % n;
v1 = n.BarrettReduction(v1 * v1, n, constant);
v1 = (v1 - ((Q_k * Q) << 1)) % n;
if (flag)
flag = false;
else
Q_k = n.BarrettReduction(Q_k * Q_k, n, constant);
Q_k = (Q_k * Q) % n;
}
else
{
// index doubling
u1 = ((u1 * v) - Q_k) % n;
v1 = ((v * v1) - (P * Q_k)) % n;
v = n.BarrettReduction(v * v, n, constant);
v = (v - (Q_k << 1)) % n;
if (flag)
{
Q_k = Q % n;
flag = false;
}
else
Q_k = n.BarrettReduction(Q_k * Q_k, n, constant);
}
mask >>= 1;
}
mask = 0x80000000;
}
// at this point u1 = u(n+1) and v = v(n)
// since the last bit always 1, we need to transform u1 to u(2n+1) and v to v(2n+1)
u1 = ((u1 * v) - Q_k) % n;
v = ((v * v1) - (P * Q_k)) % n;
if (flag)
flag = false;
else
Q_k = n.BarrettReduction(Q_k * Q_k, n, constant);
Q_k = (Q_k * Q) % n;
for (int i = 0; i < s; i++)
{
// index doubling
u1 = (u1 * v) % n;
v = ((v * v) - (Q_k << 1)) % n;
if (flag)
{
Q_k = Q % n;
flag = false;
}
else
Q_k = n.BarrettReduction(Q_k * Q_k, n, constant);
}
result[0] = u1;
result[1] = v;
result[2] = Q_k;
return result;
}
//***********************************************************************
// Overloading of addition operator
//***********************************************************************
public static BigInteger operator +(BigInteger bi1, BigInteger bi2)
{
BigInteger result = new BigInteger();
result.dataLength = (bi1.dataLength > bi2.dataLength) ? bi1.dataLength : bi2.dataLength;
long carry = 0;
for (int i = 0; i < result.dataLength; i++)
{
long sum = (long)bi1.data[i] + (long)bi2.data[i] + carry;
carry = sum >> 32;
result.data[i] = (uint)(sum & 0xFFFFFFFF);
}
if (carry != 0 && result.dataLength < maxLength)
{
result.data[result.dataLength] = (uint)(carry);
result.dataLength++;
}
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
// overflow check
int lastPos = maxLength - 1;
if ((bi1.data[lastPos] & 0x80000000) == (bi2.data[lastPos] & 0x80000000) &&
(result.data[lastPos] & 0x80000000) != (bi1.data[lastPos] & 0x80000000))
{
throw (new ArithmeticException());
}
return result;
}
//***********************************************************************
// Fast calculation of modular reduction using Barrett's reduction.
// Requires x < b^(2k), where b is the base. In this case, base is
// 2^32 (uint).
//
// Reference [4]
//***********************************************************************
private BigInteger BarrettReduction(BigInteger x, BigInteger n, BigInteger constant)
{
int k = n.dataLength,
kPlusOne = k + 1,
kMinusOne = k - 1;
BigInteger q1 = new BigInteger();
// q1 = x / b^(k-1)
for (int i = kMinusOne, j = 0; i < x.dataLength; i++, j++)
q1.data[j] = x.data[i];
q1.dataLength = x.dataLength - kMinusOne;
if (q1.dataLength <= 0)
q1.dataLength = 1;
BigInteger q2 = q1 * constant;
BigInteger q3 = new BigInteger();
// q3 = q2 / b^(k+1)
for (int i = kPlusOne, j = 0; i < q2.dataLength; i++, j++)
q3.data[j] = q2.data[i];
q3.dataLength = q2.dataLength - kPlusOne;
if (q3.dataLength <= 0)
q3.dataLength = 1;
// r1 = x mod b^(k+1)
// i.e. keep the lowest (k+1) words
BigInteger r1 = new BigInteger();
int lengthToCopy = (x.dataLength > kPlusOne) ? kPlusOne : x.dataLength;
for (int i = 0; i < lengthToCopy; i++)
r1.data[i] = x.data[i];
r1.dataLength = lengthToCopy;
// r2 = (q3 * n) mod b^(k+1)
// partial multiplication of q3 and n
BigInteger r2 = new BigInteger();
for (int i = 0; i < q3.dataLength; i++)
{
if (q3.data[i] == 0) continue;
ulong mcarry = 0;
int t = i;
for (int j = 0; j < n.dataLength && t < kPlusOne; j++, t++)
{
// t = i + j
ulong val = ((ulong)q3.data[i] * (ulong)n.data[j]) +
(ulong)r2.data[t] + mcarry;
r2.data[t] = (uint)(val & 0xFFFFFFFF);
mcarry = (val >> 32);
}
if (t < kPlusOne)
r2.data[t] = (uint)mcarry;
}
r2.dataLength = kPlusOne;
while (r2.dataLength > 1 && r2.data[r2.dataLength - 1] == 0)
r2.dataLength--;
r1 -= r2;
if ((r1.data[maxLength - 1] & 0x80000000) != 0) // negative
{
BigInteger val = new BigInteger();
val.data[kPlusOne] = 0x00000001;
val.dataLength = kPlusOne + 1;
r1 += val;
}
while (r1 >= n)
r1 -= n;
return r1;
}
//***********************************************************************
// Overloading of subtraction operator
//***********************************************************************
public static BigInteger operator -(BigInteger bi1, BigInteger bi2)
{
BigInteger result = new BigInteger();
result.dataLength = (bi1.dataLength > bi2.dataLength) ? bi1.dataLength : bi2.dataLength;
long carryIn = 0;
for (int i = 0; i < result.dataLength; i++)
{
long diff;
diff = (long)bi1.data[i] - (long)bi2.data[i] - carryIn;
result.data[i] = (uint)(diff & 0xFFFFFFFF);
if (diff < 0)
carryIn = 1;
else
carryIn = 0;
}
// roll over to negative
if (carryIn != 0)
{
for (int i = result.dataLength; i < maxLength; i++)
result.data[i] = 0xFFFFFFFF;
result.dataLength = maxLength;
}
// fixed in v1.03 to give correct datalength for a - (-b)
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
// overflow check
int lastPos = maxLength - 1;
if ((bi1.data[lastPos] & 0x80000000) != (bi2.data[lastPos] & 0x80000000) &&
(result.data[lastPos] & 0x80000000) != (bi1.data[lastPos] & 0x80000000))
{
throw (new ArithmeticException());
}
return result;
}
//***********************************************************************
// Constructor (Default value provided by a string of digits of the
// specified base)
//
// Example (base 10)
// -----------------
// To initialize "a" with the default value of 1234 in base 10
// BigInteger a = new BigInteger("1234", 10)
//
// To initialize "a" with the default value of -1234
// BigInteger a = new BigInteger("-1234", 10)
//
// Example (base 16)
// -----------------
// To initialize "a" with the default value of 0x1D4F in base 16
// BigInteger a = new BigInteger("1D4F", 16)
//
// To initialize "a" with the default value of -0x1D4F
// BigInteger a = new BigInteger("-1D4F", 16)
//
// Note that string values are specified in the <sign><magnitude>
// format.
//
//***********************************************************************
public BigInteger(string value, int radix)
{
BigInteger multiplier = new BigInteger(1);
BigInteger result = new BigInteger();
value = (value.ToUpper()).Trim();
int limit = 0;
if (value[0] == '-')
limit = 1;
for (int i = value.Length - 1; i >= limit; i--)
{
int posVal = (int)value[i];
if (posVal >= '0' && posVal <= '9')
posVal -= '0';
else if (posVal >= 'A' && posVal <= 'Z')
posVal = (posVal - 'A') + 10;
else
posVal = 9999999; // arbitrary large
if (posVal >= radix)
throw (new ArithmeticException("Invalid string in constructor."));
else
{
if (value[0] == '-')
posVal = -posVal;
result = result + (multiplier * posVal);
if ((i - 1) >= limit)
multiplier = multiplier * radix;
}
}
if (value[0] == '-') // negative values
{
if ((result.data[maxLength - 1] & 0x80000000) == 0)
throw (new ArithmeticException("Negative underflow in constructor."));
}
else // positive values
{
if ((result.data[maxLength - 1] & 0x80000000) != 0)
throw (new ArithmeticException("Positive overflow in constructor."));
}
data = new uint[maxLength];
for (int i = 0; i < result.dataLength; i++)
data[i] = result.data[i];
dataLength = result.dataLength;
}
//***********************************************************************
// Overloading of multiplication operator
//***********************************************************************
public static BigInteger operator *(BigInteger bi1, BigInteger bi2)
{
int lastPos = maxLength - 1;
bool bi1Neg = false, bi2Neg = false;
// take the absolute value of the inputs
try
{
if ((bi1.data[lastPos] & 0x80000000) != 0) // bi1 negative
{
bi1Neg = true; bi1 = -bi1;
}
if ((bi2.data[lastPos] & 0x80000000) != 0) // bi2 negative
{
bi2Neg = true; bi2 = -bi2;
}
}
catch (Exception) { }
BigInteger result = new BigInteger();
// multiply the absolute values
try
{
for (int i = 0; i < bi1.dataLength; i++)
{
if (bi1.data[i] == 0) continue;
ulong mcarry = 0;
for (int j = 0, k = i; j < bi2.dataLength; j++, k++)
{
// k = i + j
ulong val = ((ulong)bi1.data[i] * (ulong)bi2.data[j]) +
(ulong)result.data[k] + mcarry;
result.data[k] = (uint)(val & 0xFFFFFFFF);
mcarry = (val >> 32);
}
if (mcarry != 0)
result.data[i + bi2.dataLength] = (uint)mcarry;
}
}
catch (Exception)
{
throw (new ArithmeticException("Multiplication overflow."));
}
result.dataLength = bi1.dataLength + bi2.dataLength;
if (result.dataLength > maxLength)
result.dataLength = maxLength;
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
// overflow check (result is -ve)
if ((result.data[lastPos] & 0x80000000) != 0)
{
if (bi1Neg != bi2Neg && result.data[lastPos] == 0x80000000) // different sign
{
// handle the special case where multiplication produces
// a max negative number in 2's complement.
if (result.dataLength == 1)
return result;
else
{
bool isMaxNeg = true;
for (int i = 0; i < result.dataLength - 1 && isMaxNeg; i++)
{
if (result.data[i] != 0)
isMaxNeg = false;
}
if (isMaxNeg)
return result;
}
}
throw (new ArithmeticException("Multiplication overflow."));
}
// if input has different signs, then result is -ve
if (bi1Neg != bi2Neg)
return -result;
return result;
}
//***********************************************************************
// Returns gcd(this, bi)
//***********************************************************************
public BigInteger gcd(BigInteger bi)
{
BigInteger x;
BigInteger y;
if ((data[maxLength - 1] & 0x80000000) != 0) // negative
x = -this;
else
x = this;
if ((bi.data[maxLength - 1] & 0x80000000) != 0) // negative
y = -bi;
else
y = bi;
BigInteger g = y;
while (x.dataLength > 1 || (x.dataLength == 1 && x.data[0] != 0))
{
g = x;
x = y % x;
y = g;
}
return g;
}
//***********************************************************************
// Overloading of unary >> operators
//***********************************************************************
public static BigInteger operator >>(BigInteger bi1, int shiftVal)
{
BigInteger result = new BigInteger(bi1);
result.dataLength = shiftRight(result.data, shiftVal);
if ((bi1.data[maxLength - 1] & 0x80000000) != 0) // negative
{
for (int i = maxLength - 1; i >= result.dataLength; i--)
result.data[i] = 0xFFFFFFFF;
uint mask = 0x80000000;
for (int i = 0; i < 32; i++)
{
if ((result.data[result.dataLength - 1] & mask) != 0)
break;
result.data[result.dataLength - 1] |= mask;
mask >>= 1;
}
result.dataLength = maxLength;
}
return result;
}
//***********************************************************************
// Computes the Jacobi Symbol for a and b.
// Algorithm adapted from [3] and [4] with some optimizations
//***********************************************************************
public static int Jacobi(BigInteger a, BigInteger b)
{
// Jacobi defined only for odd integers
if ((b.data[0] & 0x1) == 0)
throw (new ArgumentException("Jacobi defined only for odd integers."));
if (a >= b) a %= b;
if (a.dataLength == 1 && a.data[0] == 0) return 0; // a == 0
if (a.dataLength == 1 && a.data[0] == 1) return 1; // a == 1
if (a < 0)
{
if ((((b - 1).data[0]) & 0x2) == 0) //if( (((b-1) >> 1).data[0] & 0x1) == 0)
return Jacobi(-a, b);
else
return -Jacobi(-a, b);
}
int e = 0;
for (int index = 0; index < a.dataLength; index++)
{
uint mask = 0x01;
for (int i = 0; i < 32; i++)
{
if ((a.data[index] & mask) != 0)
{
index = a.dataLength; // to break the outer loop
break;
}
mask <<= 1;
e++;
}
}
BigInteger a1 = a >> e;
int s = 1;
if ((e & 0x1) != 0 && ((b.data[0] & 0x7) == 3 || (b.data[0] & 0x7) == 5))
s = -1;
if ((b.data[0] & 0x3) == 3 && (a1.data[0] & 0x3) == 3)
s = -s;
if (a1.dataLength == 1 && a1.data[0] == 1)
return s;
else
return (s * Jacobi(b % a1, a1));
}
//***********************************************************************
// Overloading of the NEGATE operator (2's complement)
//***********************************************************************
public static BigInteger operator -(BigInteger bi1)
{
// handle neg of zero separately since it'll cause an overflow
// if we proceed.
if (bi1.dataLength == 1 && bi1.data[0] == 0)
return (new BigInteger());
BigInteger result = new BigInteger(bi1);
// 1's complement
for (int i = 0; i < maxLength; i++)
result.data[i] = (uint)(~(bi1.data[i]));
// add one to result of 1's complement
long val, carry = 1;
int index = 0;
while (carry != 0 && index < maxLength)
{
val = (long)(result.data[index]);
val++;
result.data[index] = (uint)(val & 0xFFFFFFFF);
carry = val >> 32;
index++;
}
if ((bi1.data[maxLength - 1] & 0x80000000) == (result.data[maxLength - 1] & 0x80000000))
throw (new ArithmeticException("Overflow in negation.\n"));
result.dataLength = maxLength;
while (result.dataLength > 1 && result.data[result.dataLength - 1] == 0)
result.dataLength--;
return result;
}
//***********************************************************************
// Returns the modulo inverse of this. Throws ArithmeticException if
// the inverse does not exist. (i.e. gcd(this, modulus) != 1)
//***********************************************************************
public BigInteger modInverse(BigInteger modulus)
{
BigInteger[] p = { 0, 1 };
BigInteger[] q = new BigInteger[2]; // quotients
BigInteger[] r = { 0, 0 }; // remainders
int step = 0;
BigInteger a = modulus;
BigInteger b = this;
while (b.dataLength > 1 || (b.dataLength == 1 && b.data[0] != 0))
{
BigInteger quotient = new BigInteger();
BigInteger remainder = new BigInteger();
if (step > 1)
{
BigInteger pval = (p[0] - (p[1] * q[0])) % modulus;
p[0] = p[1];
p[1] = pval;
}
if (b.dataLength == 1)
singleByteDivide(a, b, quotient, remainder);
else
multiByteDivide(a, b, quotient, remainder);
/*
Console.WriteLine(quotient.dataLength);
Console.WriteLine("{0} = {1}({2}) + {3} p = {4}", a.ToString(10),
b.ToString(10), quotient.ToString(10), remainder.ToString(10),
p[1].ToString(10));
*/
q[0] = q[1];
r[0] = r[1];
q[1] = quotient; r[1] = remainder;
a = b;
b = remainder;
step++;
}
if (r[0].dataLength > 1 || (r[0].dataLength == 1 && r[0].data[0] != 1))
throw (new ArithmeticException("No inverse!"));
BigInteger result = ((p[0] - (p[1] * q[0])) % modulus);
if ((result.data[maxLength - 1] & 0x80000000) != 0)
result += modulus; // get the least positive modulus
return result;
}
//***********************************************************************
// Returns a value that is equivalent to the integer square root
// of the BigInteger.
//
// The integer square root of "this" is defined as the largest integer n
// such that (n * n) <= this
//
//***********************************************************************
public BigInteger sqrt()
{
uint numBits = (uint)this.bitCount();
if ((numBits & 0x1) != 0) // odd number of bits
numBits = (numBits >> 1) + 1;
else
numBits = (numBits >> 1);
uint bytePos = numBits >> 5;
byte bitPos = (byte)(numBits & 0x1F);
uint mask;
BigInteger result = new BigInteger();
if (bitPos == 0)
mask = 0x80000000;
else
{
mask = (uint)1 << bitPos;
bytePos++;
}
result.dataLength = (int)bytePos;
for (int i = (int)bytePos - 1; i >= 0; i--)
{
while (mask != 0)
{
// guess
result.data[i] ^= mask;
// undo the guess if its square is larger than this
if ((result * result) > this)
result.data[i] ^= mask;
mask >>= 1;
}
mask = 0x80000000;
}
return result;
}
//***********************************************************************
// Returns the k_th number in the Lucas Sequence reduced modulo n.
//
// Uses index doubling to speed up the process. For example, to calculate V(k),
// we maintain two numbers in the sequence V(n) and V(n+1).
//
// To obtain V(2n), we use the identity
// V(2n) = (V(n) * V(n)) - (2 * Q^n)
// To obtain V(2n+1), we first write it as
// V(2n+1) = V((n+1) + n)
// and use the identity
// V(m+n) = V(m) * V(n) - Q * V(m-n)
// Hence,
// V((n+1) + n) = V(n+1) * V(n) - Q^n * V((n+1) - n)
// = V(n+1) * V(n) - Q^n * V(1)
// = V(n+1) * V(n) - Q^n * P
//
// We use k in its binary expansion and perform index doubling for each
// bit position. For each bit position that is set, we perform an
// index doubling followed by an index addition. This means that for V(n),
// we need to update it to V(2n+1). For V(n+1), we need to update it to
// V((2n+1)+1) = V(2*(n+1))
//
// This function returns
// [0] = U(k)
// [1] = V(k)
// [2] = Q^n
//
// Where U(0) = 0 % n, U(1) = 1 % n
// V(0) = 2 % n, V(1) = P % n
//***********************************************************************
public static BigInteger[] LucasSequence(BigInteger P, BigInteger Q,
BigInteger k, BigInteger n)
{
if (k.dataLength == 1 && k.data[0] == 0)
{
BigInteger[] result = new BigInteger[3];
result[0] = 0; result[1] = 2 % n; result[2] = 1 % n;
return result;
}
// calculate constant = b^(2k) / m
// for Barrett Reduction
BigInteger constant = new BigInteger();
int nLen = n.dataLength << 1;
constant.data[nLen] = 0x00000001;
constant.dataLength = nLen + 1;
constant = constant / n;
// calculate values of s and t
int s = 0;
for (int index = 0; index < k.dataLength; index++)
{
uint mask = 0x01;
for (int i = 0; i < 32; i++)
{
if ((k.data[index] & mask) != 0)
{
index = k.dataLength; // to break the outer loop
break;
}
mask <<= 1;
s++;
}
}
BigInteger t = k >> s;
//Console.WriteLine("s = " + s + " t = " + t);
return LucasSequenceHelper(P, Q, t, n, constant, s);
}
private static byte[] GetPaddedValue(BigInteger value)
{
byte[] result = value.getBytes();
int length = (1024 >> 3);
if (result.Length >= length)
return result;
// left-pad 0x00 value on the result (same integer, correct length)
byte[] padded = new byte[length];
System.Buffer.BlockCopy(result, 0, padded, (length - result.Length), result.Length);
// temporary result may contain decrypted (plaintext) data, clear it
Array.Clear(result, 0, result.Length);
return padded;
}
//***********************************************************************
// Private function that supports the division of two numbers with
// a divisor that has only 1 digit.
//***********************************************************************
private static void singleByteDivide(BigInteger bi1, BigInteger bi2,
BigInteger outQuotient, BigInteger outRemainder)
{
uint[] result = new uint[maxLength];
int resultPos = 0;
// copy dividend to reminder
for (int i = 0; i < maxLength; i++)
outRemainder.data[i] = bi1.data[i];
outRemainder.dataLength = bi1.dataLength;
while (outRemainder.dataLength > 1 && outRemainder.data[outRemainder.dataLength - 1] == 0)
outRemainder.dataLength--;
ulong divisor = (ulong)bi2.data[0];
int pos = outRemainder.dataLength - 1;
ulong dividend = (ulong)outRemainder.data[pos];
//Console.WriteLine("divisor = " + divisor + " dividend = " + dividend);
//Console.WriteLine("divisor = " + bi2 + "\ndividend = " + bi1);
if (dividend >= divisor)
{
ulong quotient = dividend / divisor;
result[resultPos++] = (uint)quotient;
outRemainder.data[pos] = (uint)(dividend % divisor);
}
pos--;
while (pos >= 0)
{
//Console.WriteLine(pos);
dividend = ((ulong)outRemainder.data[pos + 1] << 32) + (ulong)outRemainder.data[pos];
ulong quotient = dividend / divisor;
result[resultPos++] = (uint)quotient;
outRemainder.data[pos + 1] = 0;
outRemainder.data[pos--] = (uint)(dividend % divisor);
//Console.WriteLine(">>>> " + bi1);
}
outQuotient.dataLength = resultPos;
int j = 0;
for (int i = outQuotient.dataLength - 1; i >= 0; i--, j++)
outQuotient.data[j] = result[i];
for (; j < maxLength; j++)
outQuotient.data[j] = 0;
while (outQuotient.dataLength > 1 && outQuotient.data[outQuotient.dataLength - 1] == 0)
outQuotient.dataLength--;
if (outQuotient.dataLength == 0)
outQuotient.dataLength = 1;
while (outRemainder.dataLength > 1 && outRemainder.data[outRemainder.dataLength - 1] == 0)
outRemainder.dataLength--;
}