A comparative analysis of biometric secret-key binding schemes based on QIM and Wyner-Ziv coding

Biometric secret-key binding inherently requires signal processing and error correction schemes due to noisy measurement readings. Two previously proposed strategies, Quantization Index Modulation (QIM) and Wyner-Ziv (WZ) coding, are studied in the context of bio metric key binding. We characterize the tradeoff between key rate leakage and key rate-reconstruction distortion, showing that while WZ coding has a better rate-leakage tradeoff than QIM, the latter has a better rate-reconstruction tradeoff. A new strategy is proposed to combine the merits of these schemes. Known as distortion-enhanced Wyner-Ziv coding (DE-WZ), this scheme is demonstrated to exhibit improved flexibility based on numerical results for a uniform source model and scalar quantization.