Generating and verifying 2FA OTP using Chilkat CkCrypt2

Question

a little help needed. I have a method that generates a otpauth string to be used with Google Authenticator

CkCrypt2 crypt;
CkString encodedString;
CkByteData inputData;
inputData.append2(secretKey.c_str(), secretKey.length());

bool success = crypt.Encode(inputData, "base32", encodedString);

stringstream uriStream;
uriStream << "otpauth://totp/" << username << "?secret=" << encodedString;
string uri = uriStream.str();

This then generates a QR code image, all seems fine at this point.

I then have a method to verify the OTP supplied by the user to a system generated OTP

CkCrypt2 crypt;
string origSecretKey; //this gets set earlier in the method by retrieving it from the database

const char* otp = crypt.totp(origSecretKey.c_str(), "base32", "0", "", 30, 6, -1, "sha1");

cstring strOtp(otp);

bool success = (m_twoFactorCode == strOtp);

No matter what happens, the 6-digit OTPs never match. Any help very much appreciated.

Here is how I generate the QR code

BOOL CUserAdminGrid::GenerateQRCode(const std::string& text, int size, int scale, const std::string& filename) {
QRcode* qrcode = QRcode_encodeString(text.c_str(), 0, QR_ECLEVEL_L, QR_MODE_8, 1);

if (qrcode) {
    int qrSize = qrcode->width;
    int newQrSize = qrSize * scale;

    FILE* fp = fopen(filename.c_str(), "wb");
    if (fp) {
        png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
        png_infop info_ptr = png_create_info_struct(png_ptr);
        png_init_io(png_ptr, fp);
        png_set_IHDR(png_ptr, info_ptr, newQrSize, newQrSize, 8, PNG_COLOR_TYPE_RGB_ALPHA,
            PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);

        png_write_info(png_ptr, info_ptr);

        png_bytep row = new png_byte[newQrSize * 4];

        for (int y = 0; y < newQrSize; ++y) {
            int qy = y / scale;

            png_bytep p = row;
            for (int x = 0; x < newQrSize; ++x) {
                int qx = x / scale;
                int module = (qrcode->data[qy * qrSize + qx] & 0x1) ? 0 : 255;

                *p++ = 255; // Red
                *p++ = 255; // Green
                *p++ = 255; // Blue
                *p++ = module; // Alpha
            }
            png_write_row(png_ptr, row);
        }

        png_write_end(png_ptr, info_ptr);

        delete[] row;
        fclose(fp);

        png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
        png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
    }

    QRcode_free(qrcode);
    return true;
}
else
{
    return false;
}

}

Generating and verifying 2FA OTP using Chilkat CkCrypt2

0 Answers0