SipHash is ARX-based pseudorandom function optimized for short inputs. It was developed as a hash table lookup function, but it is also used for MAC generation. At the time of writing, there was no side-channel attack on SipHash known to us. This work is about application of CPA attack on SipHash. Attack was performed on ChipWhisperer CW308 UFO Board with STM32F0 target. Approximately 800 power traces were needed for succesful attack. Leakage information from XOR was used to attack cipher key. The main contribution of this work is power model of binary addition including carry propagation.