Authentication and key agreement with perfect forward secrecy
Systems and methods for providing authentication key agreement (AKA) with perfect forward secrecy (PFS) are disclosed. In one embodiment, a network according to the disclosure may receive an attach request from a UE, provide an authentication request including a network support indicator to a network resource, receive an authentication token from the network resource, such that the authentication token includes an indication that a network supports PFS, provide the authentication token to the UE, receive an authentication response including a UE public key value, obtain a network public key value and a network private key value, determine a shared key value based on the network private key value and the UE public key value, bind the shared key value with a session key value to create a bound shared key value, and use the bound shared key value to protect subsequent network traffic.
1. A method for providing an authentication and key agreement protocol with perfect forward secrecy (PFS) between a user equipment and a network, the method comprising:
generating, with the user equipment, an attach request;
receiving, with the user equipment, an authentication token from the network, that includes an indication of PFS support by the network;
determining, with the user equipment, whether the network supports PFS;
transmitting, with the user equipment, a UE public key value to the network;
receiving, with the user equipment, a network public key value from the network;
determining, with the user equipment, a shared key value based on the network public key value and a UE private key value;
binding, with the user equipment, the shared key value with a session key value to create a bound shared key value; and
utilizing, with the user equipment, the bound shared key value to protect subsequent traffic to the network.
2. The method of claim 1 wherein the attach request includes an indication that the user equipment supports PFS.
3. The method of claim 1 wherein generating, with the user equipment, an attach request comprises generating one of a service request, tracking area request, or location update request.
4. The method of claim 1 wherein binding, with the user equipment, the shared key value with the session key value comprises determining a cryptographic hash of the shared key value and/or the session key value.
5. The method of claim 1 wherein the session key value is K ASME .
6. The method of claim 1 wherein the session key value is at least one of a Cipher Key (CK) or an Integrity Key (IK).
7. The method of claim 1 wherein providing the UE public key value to the network includes generating, with the user equipment, an ephemeral Diffie-Hellman pair using elliptic-curve cryptography.
8. The method of claim 1 wherein providing the UE public key value to the network includes generating, with the user equipment, an ephemeral Diffie-Hellman pair using finite field arithmetic.
9. The method of claim 1 , comprising:
refusing a connection to the network if the UE determines that the network does not support PFS.
10. The method of claim 1 , wherein the authentication token includes an authentication management field (AMF) bit value configured to indicate that the network supports PFS.
11. An apparatus for providing an authentication and key agreement protocol with perfect forward secrecy (PFS) between user equipment (UE) and a network, the apparatus comprising:
a memory;
at least one processor operably coupled to the memory and configured to:
receive an attach request from a UE;
transmit an authentication request including a network support indicator to a network resource;
receive an authentication token from the network resource, wherein the authentication token includes an indication that a network supports PFS;
transmit the authentication token to the UE;
receive an authentication response including a UE public key value;
deny the attach request if the authentication response is not an expected response;
if the authentication response is the expected response, then
obtain a network public key value and a network private key value;
determine a shared key value based on the network private key value and the UE public key value;
bind the shared key value with a session key value to create a bound shared key value; and
use the bound shared key value to protect subsequent network traffic.
12. The apparatus of claim 11 wherein the authentication token is integrity protected between the UE and the network resource.
13. The apparatus of claim 11 wherein the at least one processor is configured to receive the attach request from the UE by receiving one of a service request, tracking area request or location update request instead of an attach request.
14. The apparatus of claim 11 wherein the at least one processor is configured to determine a cryptographic hash of the shared key value and the session key value.
15. The apparatus of claim 11 wherein the session key value is at least one of K ASME , Cipher Key (CK), or Integrity Key (IK).
16. The apparatus of claim 11 wherein the shared key value is determined by one of elliptic-curve cryptology or finite field arithmetic.
17. The apparatus of claim 11 wherein the attach request includes an indication that the UE supports PFS.
18. The apparatus of claim 11 wherein the authentication token includes an authentication management field (AMF) bit value to indicate that the network supports PFS.