Section: 5.1.4 Data integrity
Content: The following security features are provided with respect to integrity of data on the network access link: - integrity algorithm agreement: the property that the MS and the SN can securely negotiate the integrity algorithm that they shall use subsequently; - integrity key agreement: the property that the MS and the SN agree on an integrity key that they may use subsequently; - data integrity and origin authentication of signalling data: the property that the receiving entity (MS or SN) is able to verify that signalling data has not been modified in an unauthorised way since it was sent by the sending entity (SN or MS) and that the data origin of the signalling data received is indeed the one claimed; Integrity key agreement is realised in the course of the execution of the mechanism for authentication and key agreement (see 6.3). Integrity algorithm agreement is realised by means of a mechanism for security mode negotiation between the user and the network (see 6.4.5). This mechanism also enables the selected integrity algorithm and the agreed integrity key to be applied in the way described in 6.5.