Hardware Trojans in wireless cryptographic ICs: Silicon demonstration & detection method evaluation

We present a silicon implementation of a hardware Trojan, which is capable of leaking the secret key of a wireless cryptographic integrated circuit (IC) consisting of an Advanced Encryption Standard (AES) core and an Ultra-Wide-Band (UWB) transmitter. With its impact carefully hidden in the transmission specification margins allowed for process variations, this hardware Trojan cannot be detected by production testing methods of either the digital or the analog part of the IC and does not violate the transmission protocol or any system-level specifications. Nevertheless, the informed adversary, who knows what to look for in the transmission power waveform, is capable of retrieving the 128-bit AES key, which is leaked with every 128-bit ciphertext block sent by the UWB transmitter. Using silicon measurements from 40 chips fabricated in TSMC´s 0.35μm technology, we also assess the effectiveness of a side channel-based statistical analysis method in detecting this hardware Trojan.