A User Authentication Scheme Using Physiological and Behavioral Biometrics for Multitouch Devices

Algorithm 3

Check right-hand algorithm.

Input: array 𝑅={𝑟_𝑗∣𝑟_𝑗=(𝑥_𝑗,𝑦_𝑗),0≤𝑗≤4} //𝑅 is non-order finger coordinate of the user input

Output: RHS //RHS is the right-hand side of the input user

(1) sort(𝐹_𝑖) by 𝑥_𝑖 in ascending order

(2) assing 𝑡=𝑘, which max(𝑦_𝑘) of 𝐹_𝑖 //Detect thumb by finding the maximum position of 𝑦-axis

(3) switch  𝑡:

(4) Case  0: //if the 𝑅[0] is thumb (Figure 6, Case  1)

(5) assign 𝐹_𝑖=1; //𝑅[1] is the coordinate of index finger

(6) assign 𝐹_𝑙=4; //𝑅[4] is the coordinate of little finger

(7) break;

(8) Case  4: //if the 𝑅[4] is thumb (Figure 6, Case  5)

(9) assign 𝐹_𝑖=3; //𝑅[3] is the coordinate of index finger

(10) assign 𝐹_𝑙=0; //𝑅[0] is the coordinate of little finger

(11) break;

(12) Case  1, 2, 3: //if 𝑅[1], 𝑅[2], or 𝑅[3] is thumb (Figure 6, Case  2, 3, and 4)

(13) assign 𝐹_𝑖=0; //𝑅[0] is the coordinate of index finger

(14) assign 𝐹_𝑙=4; //𝑅[4] is the coordinate of little finger

(15) break;

(16) if  𝑑(𝐹_𝑡,𝐹_𝑖)<𝑑(𝐹_𝑡,𝐹_𝑙)  then output the user is left-hand

(17) else output the user is right-hand