User datagram protocol (UDP) is widely used to send real time data which is not sensitive to packet loss such as short period sensor data. Since UDP header provides checksum field, this field can be used for increasing the UDP performance, for instance, providing partial error check service such as in UDP-Lite. The checksum field can also be used for encryption key transfer for dynamic encryption system to provide more secured datagram. This paper examines UDP checksum usage for either error check or security key exchange. UDP-Lite works well for erroneous environment by suppressing packet loss up to 4%. But encryption key distribution may be a good option as it provides more secure data, mainly in lossless environment, where packet loss is less than 1%. For losses traffic tolerant, UDP is a good choice if low delay is desired.