In the context of facilitating a circuit switched to packet switched handover of a call in a cellular communication system, a first node (e.g., packet switched target node) generates a security context for a client whose call is being handed over. This involves the first node receiving at least one cryptographic key from a second node (e.g., a circuit switched node supporting the existing connection) and receiving identities of security algorithms supported by the client from a third node (e.g., a packet switched node supporting the existing connection); The first node uses the at least one cryptographic key and the identities to generate the security context for the client.