void WinCAPICryptoKeyDSA::loadParamsFromKey()

in xsec/enc/WinCAPI/WinCAPICryptoKeyDSA.cpp [578:674]

• 68 lines of code
• 18 McCabe index (conditional complexity)

void WinCAPICryptoKeyDSA::loadParamsFromKey(void) {

	if (m_key == 0) {

		if (m_keySpec == 0)
			return;

		// See of we can get the user key
		if (!CryptGetUserKey(m_p, m_keySpec, &m_key))
			return;

	}

	// Export key into a keyblob
	BOOL fResult;
	DWORD blobLen;

	fResult = CryptExportKey(
		m_key,
		0,
		PUBLICKEYBLOB,
		0,
		NULL,
		&blobLen);
	
	if (fResult == 0 || blobLen < 1) {
		throw XSECCryptoException(XSECCryptoException::DSAError,
			"WinCAPI:DSA - Error exporting public key");
	}

	BYTE * blob;
	XSECnew(blob, BYTE[blobLen]);
	ArrayJanitor<BYTE> j_blob(blob);

	fResult = CryptExportKey(
		m_key,
		0,
		PUBLICKEYBLOB,
		0,
		blob,
		&blobLen);
	
	if (fResult == 0 || blobLen < 1) {
		throw XSECCryptoException(XSECCryptoException::DSAError,
			"WinCAPI:DSA - Error exporting public key");
	}

	DSSPUBKEY * pk = (DSSPUBKEY *) ( blob + WINCAPI_BLOBHEADERLEN );
	DWORD keyLen = pk->bitlen / 8;

	// Copy the keys
	
	BYTE * i = (BYTE *) ( pk );
	i += WINCAPI_DSSPUBKEYLEN;
	if (mp_P != NULL)
		delete[] mp_P;

	XSECnew(mp_P, BYTE[keyLen]);
	memcpy(mp_P, i, keyLen);
	m_PLen = keyLen;

	i+=keyLen;

	if (mp_Q != NULL)
		delete[] mp_Q;

	m_QLen = 20;
	while (i[m_QLen - 1] == 0 && m_QLen > 0)
		m_QLen--;
	XSECnew(mp_Q, BYTE[m_QLen]);
	memcpy(mp_Q, i, m_QLen);
	
	i+=20;

	if (mp_G != NULL)
		delete[] mp_G;
	
	m_GLen = keyLen;
	while(i[m_GLen - 1] == 0 && m_GLen > 0)
		m_GLen--;

	XSECnew(mp_G, BYTE[m_GLen]);
	memcpy(mp_G, i, m_GLen);

	i+=keyLen;

	if (mp_Y != NULL)
		delete[] mp_Y;

	m_YLen = keyLen;
	while (i[m_YLen] == 0 && m_YLen > 0)
		m_YLen--;

	XSECnew(mp_Y, BYTE[m_YLen]);
	memcpy(mp_Y, i, m_YLen);

}