摘要 |
A path switch message in a mobile radio access network is protected as the message is sent over a user plane interface that may be insecure (e.g. lacks integrity and/or confidentiality protection). According to the invention a UE provides an AP with a fresh integrity key over an already existing and secure RAN channel enabling AP to use the integrity key to integrity protect information sent to a UPN. Specifically, UE derives locally at least a user plane key K1. The key derivation is done at authentication e.g. when performing an AKA procedure. On the network side CPN derives the same key K1 for delivery to UPN. At handover, the UE generates a fresh integrity key K3 by applying a Key Derivation Function (KDF) with at least the UP key K1 and a nonce, e.g. a sequence number.
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