A Composable Multifactor Identity Authentication and Authorization Scheme for 5G Services

Algorithm 1

Composable three-factor authentication.

	Require: the user identity ; the password ; the biometric data ; the smart card.
	Ensure: authentication result: 0 for failure; 1 for success.
(1)	: 5G user sends a service request message including and security level of the access service read from the smart card.
(2)	: checks the highest security level in the service request message. If, then
	Output 1 and Terminate the authentication process.
	Else if, then go to Step 3.
	Else if, then go to Step 8.
	Else if, then go to Step 3.
	sends an attach response to notify .
(3)	5G user chooses a new random number and sends to .
(4)	Upon the receipt of the message, works as follows.
(i)	If the timestamp is invalid, Output 0. Else, go ahead.
(ii)	Search by in the database and decrypt with to obtain .
(iii)	Generate a new random number and compute and .
(iv)	Send to user .
(5)	Upon the receipt of the message, works as follows.
(i)	If the timestamp is invalid, Output 0. Else, go ahead.
(ii)	Compute and .
(iii)	Decrypt with to obtain .
(iv)	Compute . If the equation is established, then go ahead. Else, Output 0.
(v)	Compute and send to .
(6)	Upon the receipt of the message, works as follows.
(i)	If the timestamp is invalid, Output 0. Else, go ahead.
(ii)	Verify . If it is, then go ahead. Else, Output 0.
(7)	If, then output 1. Else, if, go ahead.
(8)	computes and sends to .
(9)	Upon the receipt of the message, works as follows.
(i)	If the timestamp is invalid, Output 0. Else, go ahead.
(ii)	Compute .
(iii)	Verify . If the equation is established, go ahead. Else, Output 0.
(iv)	Generate new numbers and calculate and .
(v)	Calculate and .
(vi)	Send to .
(10)	Upon the receipt of the message, works as follows.
(i)	If the timestamp is invalid, Output 0. Else, go ahead.
(ii)	Calculate and
(iii)	. If the two equations are established, then go ahead. Else, Output 0.
	Generate and .
(iv)	Replace with . Output 1.