The EAP MSK is transported between the IdP and the RP over the AAA infrastructure -- for example, through RADIUS headers. This is a particularly important privacy consideration, as any AAA proxy that has access to the EAP MSK is able to decrypt and eavesdrop on any traffic encrypted using that EAP MSK (i.e., all communications between the client and RP). This problem can be mitigated if the application protocol sets up a secure tunnel between the client and the RP and performs a cryptographic binding between the tunnel and EAP MSK.