private byte[] getCompleteHw()
{
byte[] bDerHashIdent = Hex.Decode(Datablock.getInstance().HashFunctionIdent.DERIdent);
byte[] bMessage = Datablock.getInstance().Message;
HashFunctionIdent hashIdent = Datablock.getInstance().HashFunctionIdent;
byte[] hashDigest = Hashfunction.generateHashDigest(ref bMessage, ref hashIdent);
byte[] returnArray = new byte[bDerHashIdent.Length + Hashfunction.getDigestSize()];
Array.Copy(bDerHashIdent, 0, returnArray, 0, bDerHashIdent.Length);
Array.Copy(hashDigest, 0, returnArray, returnArray.Length - hashDigest.Length, hashDigest.Length);
return(returnArray);
}
public override bool GenerateSignature()
{
this.SendGuiLogMsg("Message Generation started", NotificationLevel.Info);
this.m_KeyLength = RsaKey.Instance.RsaKeySize;
int hashDigestLength = Hashfunction.getDigestSize() * 8; // weil Size in Byte zurückgegeben wird
int hashIdentLength = Datablock.getInstance().HashFunctionIdent.DERIdent.Length * 4; // weil ein zeichen im string = 4 bit
int keyLength = this.m_KeyLength;
BigInteger derIdent = new BigInteger(Datablock.getInstance().HashFunctionIdent.DERIdent, 16);
BigInteger datablockLength = BigInteger.ValueOf(hashDigestLength + hashIdentLength + 8); // Länge Datenblock inkl 0-Byte (=8Bit)
bool isDivByThree = false;
BigInteger N = null;
BigInteger datablock = null;
while (false == isDivByThree)
{
byte[] bMessage = Datablock.getInstance().Message;
HashFunctionIdent hashIdent = Datablock.getInstance().HashFunctionIdent;
BigInteger hashDigest = new BigInteger(1, Hashfunction.generateHashDigest(ref bMessage, ref hashIdent));
// T*2^160 + H
datablock = derIdent.Multiply(BigInteger.Two.Pow(hashDigestLength)).Add(hashDigest); // Datablock erstellen; T=HashFuncIdent; H=HashDigest
N = (BigInteger.Two.Pow(datablockLength.IntValue)).Subtract(datablock); // N muss vielfaches von 3 sein
if (0 == (N.Mod(BigInteger.Three)).IntValue)
{
isDivByThree = true;
}
else
{
byte[] extSign = Encoding.ASCII.GetBytes(ChangeSign);
byte[] tmp = new byte[Datablock.getInstance().Message.Length + extSign.Length];
Array.Copy(Datablock.getInstance().Message, tmp, Datablock.getInstance().Message.Length);
Array.Copy(extSign, 0, tmp, Datablock.getInstance().Message.Length, extSign.Length);
Datablock.getInstance().Message = tmp;
}
}
BigInteger sigLengthWithoutZeros = BigInteger.ValueOf(this.m_KeyLength - 15); // 15 weil die ersten 15 bit 0 sind
BigInteger startPos = BigInteger.ValueOf(this.m_dataBlockStartPos);
BigInteger endPos = startPos.Add(datablockLength);
BigInteger sigLengthDivThree = sigLengthWithoutZeros.Divide(BigInteger.Three);
BigInteger testbeta = endPos.Subtract(BigInteger.Two.Multiply(sigLengthDivThree)).Subtract(datablockLength); // sollte 34 seinbei keylength 3072
//2^3057 - 2^ (2038 + 288 + 34) == 2^3057 - 2^2360
BigInteger fakeSig = (BigInteger.Two.Pow(sigLengthWithoutZeros.IntValue)).Subtract(BigInteger.Two.Pow(2 * sigLengthDivThree.IntValue + datablockLength.IntValue + testbeta.IntValue));
// 2^3057 - 2^2360 + 2^2072 * N
fakeSig = fakeSig.Add((BigInteger.Two.Pow(startPos.IntValue)).Multiply(datablock));
fakeSig = fakeSig.Add(BigInteger.Two.Pow(startPos.IntValue - 8).Multiply(BigInteger.ValueOf(125))); // add garbage
BigInteger fakeSigResult = MathFunctions.cuberoot(fakeSig);
byte[] returnByteArray = new byte[this.m_KeyLength / 8]; // KeyLength is in bit
Array.Copy(fakeSigResult.ToByteArray(), 0, returnByteArray, returnByteArray.Length - fakeSigResult.ToByteArray().Length, fakeSigResult.ToByteArray().Length);
this.m_Signature = returnByteArray;
this.m_bSigGenerated = true;
this.OnRaiseSigGenEvent(SignatureType.Bleichenbacher);
return(true);
}