/// <summary>
/// Decodes the specified QR string.
/// </summary>
/// <param name="qrstring">The QR string.</param>
/// <returns>The payload data.</returns>
/// <exception cref="InvalidDataException">Checksum of decompressed data does not match.</exception>
public byte[] DecodeBytes(string qrstring)
{
// decode from Base32Hex
var data2 = Base32.FromBase32String(qrstring);
// data[0-1] // PayBySquare header
// data[2-3] // original data length
var originalDataLength = data2[2] + (data2[3] << 8);
// skip first 4 bytes (PayBySquare qr code header + original data length)
var payload = this.Decompress(data2, 4, originalDataLength);
// first 4 bytes is crc32
var crc = new Crc32().ComputeHash(payload, 4, originalDataLength - 4);
Array.Reverse(crc);
if (BitConverter.ToInt32(crc, 0) != BitConverter.ToInt32(payload, 0))
{
throw new InvalidDataException("Checksum of decompressed data does not match.");
}
return(payload);
}
