Unlike UMTS and LTE, it looks like WiMAX will not make use of SIM cards but instead embedded authentication information directly in the device. In a world where only private keys are used, this would bind the device to an operator, i.e. a nice look-in scheme. WiMAX however, uses X.509 certificates issued by a certificate authority. If I understand things right, operator look-in of a device is then decided by whether the public key of the certificate authority is known in public or not. It looks like Verisign for example issues X.509 certificates for WiMAX. Now my big question now is: Are the public keys of certificate authorities used for generating WiMAX X.509 certificates public knowledge? Anyone?