To secure transmission of physiological data in body sensor network（BSN）

a biometrics-based key distribution scheme is specifically designed for the intra-communications of BSN.The scheme utilizes inter-pulse interval（IPI）derived from cardiovascular signals which are collected from sensor nodes to generate independently a redundant entity identifier

which is then combined with a fuzzy commitment scheme to protect key distribution.Experimental results show that the scheme is effective.Compared with the existing scheme

the use of redundant entity identifier is effective to reduce both false rejection rate and the threshold of identification as well as to improve the speed of key distribution without compromising of the security level.