Exemplos de BigInteger::fromBinary em C++ (Cpp)

Exemplo n.º 1

bool IntegerExtractor::Decode(int inputLen, BigInteger &theInt)
{
    if(!mIsValid)
        return false;

    if(input.length()<=offset)
        return false;

    bool negative = ((PeekByte() & 0x80)!=0) ? true : false;

    while (inputLen>0 && PeekByte()==0)
    {
        offset++;
        inputLen--;
    }

    RawBuffer reg(inputLen,(unsigned char)0);

    for (int i=0; i<inputLen; i++)
    {
        reg[i] = GetByte();
    }

    /*
    	if (negative)
    	{
    		for (int i=inputLen; i<reg.length; i++)
    			reg[i] = (byte)0xff;

    		TwosComplement(reg, reg.length);
    	}*/

    theInt.fromBinary(reg);
    return mIsValid;
}

Exemplo n.º 2

ByteBufferPtr ElGamal::Decrypt(const void *theCipherText, int theCipherTextLen) const
{
    if(!IsPrivate())
        return NULL;

    const unsigned char *in = (const unsigned char*)theCipherText;
    int inOffset = 0;

    if(theCipherTextLen-inOffset<4) return NULL;
    int aNumBlocks = LongFromLittleEndian(*(int*)in);
    inOffset+=4;

    if(theCipherTextLen-inOffset < aNumBlocks*modulusLen*2-inOffset)
        return NULL;

    RawBuffer aBuf(modulusLen,(unsigned char)0);
    RawBuffer bBuf(modulusLen,(unsigned char)0);

    WriteBuffer aDecrypt;

    BigInteger a;;
    BigInteger b;

    BigInteger aPlainText;

    for(int i=0; i<aNumBlocks; i++)
    {
        aBuf.assign(in+inOffset,modulusLen);
        inOffset+=modulusLen;
        bBuf.assign(in+inOffset,modulusLen);
        inOffset+=modulusLen;

        a.fromBinary(aBuf);
        b.fromBinary(bBuf);

        if(!decrypt(a,b,aPlainText))
            return NULL;

        RawBuffer aBigIntArray;
        aPlainText.toBinary(aBigIntArray);


        if(aBigIntArray.length()==0) return NULL;
        int aPlainLen = aBigIntArray[aBigIntArray.length() - 1];

        if(aPlainLen>modulusLen - 3)
            return NULL;

        if(aBigIntArray.length() - 1 - aPlainLen < 0)
        {
            int extra = aPlainLen - (aBigIntArray.length() - 1);
            for(int j=0; j<extra; j++)
                aDecrypt.AppendByte(0);

            aDecrypt.AppendBytes(aBigIntArray.data(),aBigIntArray.length());
        }
        else
            aDecrypt.AppendBytes(aBigIntArray.data()+aBigIntArray.length()-1-aPlainLen,aPlainLen);
    }

    return aDecrypt.ToByteBuffer();
}