This paper investigates the side-channel resistance of the ChaCha20 stream cipher on 8-bit and 32-bit microcontrollers. Using the low-cost ChipWhisperer platform, we demonstrate full keystream recovery under nonce reuse via Correlation Power Analysis (CPA). For proper nonce usage, we propose a novel two-phase CPA strategy that successfully recovers key bytes in the first column of the cipher’s internal state by exploiting second-round leakage. While full key recovery remains out of reach, the results confirm exploitable leakage and highlight practical risks in ChaCha20 implementations on embedded systems.

This paper introduces a novel side-channel attack scheme targeting FPGA implementations of the SipHash cipher, a cryptographic hash function commonly used for message authentication. At the time of writing, we were unaware of any side-channel attack on hardware implementation of the SipHash. A leakage function was built that is able to compute part of the internal state after 1 round based on just a few bits of the key. Our approach is based on progressively eliminating incorrect subkeys in iterations, while adding new bits of the key we attack, rather than trying to extract the subkey directly. The total amount of key hypotheses does not exceed a limit when it becomes unfeasible to compute. In the end, all 128 bits of the SipHash key are retrieved solely from the Hamming distance of the initial state and the state after first round.

This work presents an experimental evaluation of influence of compiler optimization flags on side-channel information leakage. Sip Hash was used as a reference algorithm an ARX - based pseudorandom function optimized for short inputs. ChipWhisperer CW308 with various targets was used for the evaluation using guessing entropy of CPA and Welch's t-test. The main contribution of this paper is analysis of impact of each flag and its suitability for implementations minimizing side-channel leakage.

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.