Following a schema illustrating how the trusted authentication and transaction validation is managed.
Then the user inputs on the randomized keypad the one time code he see on the screen: 256 in this example. P1(x1,y1), P2(x2,y2), P3(x3,y3) are the inputs positions matching 2,5,6 on the one time random keypad.
Fingerprint and/or facial recognization trigger the signature of the user inputs with mobile private key stored in TEE. Then the signed random position i.e. P1, P2, P3 are sent to the nodes to be verified.