Randomness of the Generated Keys Sample Clauses

Randomness of the Generated Keys. The entropy mea- sures the randomness of the keys. In this analysis, Xxxxxxx’x Entropy values are calculated using Equation 4, in which Ki represents the ith bit of the key. Σ H = − P (Ki)log2P (Ki) (4) || || As in the sample set, we use 300 keys (30 subjects, 10 keys per subject). The entropy values of these keys are given in Figure 6. The more the entropy value approaches to 1, the more random the key is. As can be seen in this figure, 83.67% of the keys have entropy values that are greater than 0.994, and also all of the keys have entropy values that are greater than 0.98, which implies very good randomness. It is important to note that these keys are generated by hashing the common minutiae. It can be normal to have high entropy for the hash results, because the hash functions kind of randomize the input string. Therefore, the entropy values of the concatenation of common minutiae are calculated as well. The concatenation is as follows, x y type. The entropy values of these concatenations are given in Figure 7. Although the common minutiae, x.x. xxxx = 16, then the attack complexity . Σ com becomes 440 = 440! ∼= 296. entropy values decrease a little, 92.3% of the keys have entropy att 16!×(440−16)! = . |Qu| Σ = |Qu|! n com key