internal void SetFromString(Integer Result, string InString)
{
if (InString == null)
{
throw(new Exception("InString was null in SetFromString()."));
}
if (InString.Length < 1)
{
Result.SetToZero();
return;
}
Base10Number Base10N = new Base10Number();
Integer Tens = new Integer();
Integer OnePart = new Integer();
// This might throw an exception if the string is bad.
Base10N.SetFromString(InString);
Result.SetFromULong(Base10N.GetD(0));
Tens.SetFromULong(10);
for (int Count = 1; Count <= Base10N.GetIndex(); Count++)
{
OnePart.SetFromULong(Base10N.GetD(Count));
Multiplier.Multiply(OnePart, Tens);
Result.Add(OnePart);
Multiplier.MultiplyULong(Tens, 10);
}
}
// Copyright Eric Chauvin 2015 - 2018.
internal int Reduce(Integer Result, Integer ToReduce)
{
try
{
if (ToReduce.ParamIsGreater(CurrentModReductionBase))
{
Result.Copy(ToReduce);
return(Result.GetIndex());
}
if (GeneralBaseArray == null)
{
throw(new Exception("SetupGeneralBaseArray() should have already been called."));
}
Result.SetToZero();
int TopOfToReduce = ToReduce.GetIndex() + 1;
if (TopOfToReduce > GeneralBaseArray.Length)
{
throw(new Exception("The Input number should have been reduced first. HowManyToAdd > GeneralBaseArray.Length"));
}
// If it gets this far then ToReduce is at
// least this big.
int HighestCopyIndex = CurrentModReductionBase.GetIndex();
Result.CopyUpTo(ToReduce, HighestCopyIndex - 1);
int BiggestIndex = 0;
for (int Count = HighestCopyIndex; Count < TopOfToReduce; Count++)
{
// The size of the numbers in GeneralBaseArray
// are all less than the size of GeneralBase.
// This multiplication by a uint is with a
// number that is not bigger than GeneralBase.
// Compare this with the two full Muliply()
// calls done on each digit of the quotient
// in LongDivide3().
// AccumulateBase is set to a new value here.
int CheckIndex = IntMath.MultiplyUIntFromCopy(AccumulateBase, GeneralBaseArray[Count], ToReduce.GetD(Count));
if (CheckIndex > BiggestIndex)
{
BiggestIndex = CheckIndex;
}
Result.Add(AccumulateBase);
}
return(Result.GetIndex());
}
catch (Exception Except)
{
throw(new Exception("Exception in ModularReduction(): " + Except.Message));
}
}
internal void Subtract(Integer Result, Integer ToSub)
{
// This checks that the sign is equal too.
if (Result.IsEqual(ToSub))
{
Result.SetToZero();
return;
}
// ParamIsGreater() handles positive and negative values, so if the
// parameter is more toward the positive side then it's true. It's greater.
// The most common form. They are both positive.
if (!Result.IsNegative && !ToSub.IsNegative)
{
if (ToSub.ParamIsGreater(Result))
{
SubtractPositive(Result, ToSub);
return;
}
// ToSub is bigger.
TempSub1.Copy(Result);
TempSub2.Copy(ToSub);
SubtractPositive(TempSub2, TempSub1);
Result.Copy(TempSub2);
Result.IsNegative = true;
return;
}
if (Result.IsNegative && !ToSub.IsNegative)
{
TempSub1.Copy(Result);
TempSub1.IsNegative = false;
TempSub1.Add(ToSub);
Result.Copy(TempSub1);
Result.IsNegative = true;
return;
}
if (!Result.IsNegative && ToSub.IsNegative)
{
TempSub1.Copy(ToSub);
TempSub1.IsNegative = false;
Result.Add(TempSub1);
return;
}
if (Result.IsNegative && ToSub.IsNegative)
{
TempSub1.Copy(Result);
TempSub1.IsNegative = false;
TempSub2.Copy(ToSub);
TempSub2.IsNegative = false;
// -12 - -7 = -12 + 7 = -5
// Comparing the positive numbers here.
if (TempSub2.ParamIsGreater(TempSub1))
{
SubtractPositive(TempSub1, TempSub2);
Result.Copy(TempSub1);
Result.IsNegative = true;
return;
}
// -7 - -12 = -7 + 12 = 5
SubtractPositive(TempSub2, TempSub1);
Result.Copy(TempSub2);
Result.IsNegative = false;
return;
}
}
internal void Add(Integer Result, Integer ToAdd)
{
if (ToAdd.IsZero())
{
return;
}
// The most common form. They are both positive.
if (!Result.IsNegative && !ToAdd.IsNegative)
{
Result.Add(ToAdd);
return;
}
if (!Result.IsNegative && ToAdd.IsNegative)
{
TempAdd1.Copy(ToAdd);
TempAdd1.IsNegative = false;
if (TempAdd1.ParamIsGreater(Result))
{
Subtract(Result, TempAdd1);
return;
}
else
{
Subtract(TempAdd1, Result);
Result.Copy(TempAdd1);
Result.IsNegative = true;
return;
}
}
if (Result.IsNegative && !ToAdd.IsNegative)
{
TempAdd1.Copy(Result);
TempAdd1.IsNegative = false;
TempAdd2.Copy(ToAdd);
if (TempAdd1.ParamIsGreater(TempAdd2))
{
Subtract(TempAdd2, TempAdd1);
Result.Copy(TempAdd2);
return;
}
else
{
Subtract(TempAdd1, TempAdd2);
Result.Copy(TempAdd2);
Result.IsNegative = true;
return;
}
}
if (Result.IsNegative && ToAdd.IsNegative)
{
TempAdd1.Copy(Result);
TempAdd1.IsNegative = false;
TempAdd2.Copy(ToAdd);
TempAdd2.IsNegative = false;
TempAdd1.Add(TempAdd2);
Result.Copy(TempAdd1);
Result.IsNegative = true;
return;
}
}
internal bool DecryptWithQInverse(Integer EncryptedNumber,
Integer DecryptedNumber,
Integer TestDecryptedNumber,
Integer PubKeyN,
Integer PrivKInverseExponentDP,
Integer PrivKInverseExponentDQ,
Integer PrimeP,
Integer PrimeQ,
BackgroundWorker Worker)
{
Worker.ReportProgress(0, " ");
Worker.ReportProgress(0, "Top of DecryptWithQInverse().");
// QInv and the dP and dQ numbers are normally already set up before
// you start your listening socket.
ECTime DecryptTime = new ECTime();
DecryptTime.SetToNow();
// See section 5.1.2 of RFC 2437 for these steps:
// http://tools.ietf.org/html/rfc2437
// 2.2 Let m_1 = c^dP mod p.
// 2.3 Let m_2 = c^dQ mod q.
// 2.4 Let h = qInv ( m_1 - m_2 ) mod p.
// 2.5 Let m = m_2 + hq.
Worker.ReportProgress(0, "EncryptedNumber: " + IntMath.ToString10(EncryptedNumber));
// 2.2 Let m_1 = c^dP mod p.
TestForDecrypt.Copy(EncryptedNumber);
IntMathForP.ModReduction.ModularPower(TestForDecrypt, PrivKInverseExponentDP, PrimeP, true);
if (Worker.CancellationPending)
{
return(false);
}
M1ForInverse.Copy(TestForDecrypt);
// 2.3 Let m_2 = c^dQ mod q.
TestForDecrypt.Copy(EncryptedNumber);
IntMathForQ.ModReduction.ModularPower(TestForDecrypt, PrivKInverseExponentDQ, PrimeQ, true);
if (Worker.CancellationPending)
{
return(false);
}
M2ForInverse.Copy(TestForDecrypt);
// 2.4 Let h = qInv ( m_1 - m_2 ) mod p.
// How many is optimal to avoid the division?
int HowManyIsOptimal = (PrimeP.GetIndex() * 3);
for (int Count = 0; Count < HowManyIsOptimal; Count++)
{
if (M1ForInverse.ParamIsGreater(M2ForInverse))
{
M1ForInverse.Add(PrimeP);
}
else
{
break;
}
}
if (M1ForInverse.ParamIsGreater(M2ForInverse))
{
M1M2SizeDiff.Copy(M2ForInverse);
IntMath.Subtract(M1M2SizeDiff, M1ForInverse);
// Unfortunately this long Divide() has to be done.
IntMath.Divider.Divide(M1M2SizeDiff, PrimeP, Quotient, Remainder);
Quotient.AddULong(1);
Worker.ReportProgress(0, "The Quotient for M1M2SizeDiff is: " + IntMath.ToString10(Quotient));
IntMath.Multiply(Quotient, PrimeP);
M1ForInverse.Add(Quotient);
}
M1MinusM2.Copy(M1ForInverse);
IntMath.Subtract(M1MinusM2, M2ForInverse);
if (M1MinusM2.IsNegative)
{
throw(new Exception("M1MinusM2.IsNegative is true."));
}
if (QInv.IsNegative)
{
throw(new Exception("QInv.IsNegative is true."));
}
HForQInv.Copy(M1MinusM2);
IntMath.Multiply(HForQInv, QInv);
if (HForQInv.IsNegative)
{
throw(new Exception("HForQInv.IsNegative is true."));
}
if (PrimeP.ParamIsGreater(HForQInv))
{
IntMath.Divider.Divide(HForQInv, PrimeP, Quotient, Remainder);
HForQInv.Copy(Remainder);
}
// 2.5 Let m = m_2 + hq.
DecryptedNumber.Copy(HForQInv);
IntMath.Multiply(DecryptedNumber, PrimeQ);
DecryptedNumber.Add(M2ForInverse);
if (!TestDecryptedNumber.IsEqual(DecryptedNumber))
{
throw(new Exception("!TestDecryptedNumber.IsEqual( DecryptedNumber )."));
}
Worker.ReportProgress(0, " ");
Worker.ReportProgress(0, "DecryptedNumber: " + IntMath.ToString10(DecryptedNumber));
Worker.ReportProgress(0, " ");
Worker.ReportProgress(0, "TestDecryptedNumber: " + IntMath.ToString10(TestDecryptedNumber));
Worker.ReportProgress(0, " ");
Worker.ReportProgress(0, "Decrypt with QInv time seconds: " + DecryptTime.GetSecondsToNow().ToString("N2"));
Worker.ReportProgress(0, " ");
return(true);
}
