The LED cryptographic algorithm was proposed in 2011.It is an ultra-lightweight cryptographic algorithm which suitable for the implementation such as RFID Smart Card of the IoT. The structure of ultra-Lightweight cryptographic algorithm is simple. It is easily attacked by side channel attacks(SCA). Random masking is an effective method to resist attack the SCA. Completely random mask LED(CMLED) is proposed after we studied the LED indepth. The designing method of CMLED is discussed, are The principle of selected masking is proved from the f...