Function MulU

src/cryptopp/cmac.cpp:11–41

NAMESPACE_BEGIN(CryptoPP)

static void MulU(byte *k, unsigned int length)
{
	byte carry = 0;

	for (int i=length-1; i>=1; i-=2)
	{
		byte carry2 = k[i] >> 7;
		k[i] += k[i] + carry;
		carry = k[i-1] >> 7;
		k[i-1] += k[i-1] + carry2;
	}

	if (carry)
	{
		switch (length)
		{
		case 8:
			k[7] ^= 0x1b;
			break;
		case 16:
			k[15] ^= 0x87;
			break;
		case 32:
			k[30] ^= 4;
			k[31] ^= 0x23;
			break;
		default:
			throw InvalidArgument("CMAC: " + IntToString(length) + " is not a supported cipher block size");
		}
	}
}

void CMAC_Base::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
{