Patent ID: 7065340
Filing Date: 2006-06-20
Classification: H04L,H04W

Abstract:
1. A method of arranging data protection in a telecommunication system including a first mobile communication network, a second mobile communication network, and a mobile station supporting both of the mobile communication networks, the method comprising: ciphering traffic between the mobile station and the first mobile communication network using a first cipher key; calculating a second cipher key to be used for ciphering traffic between the mobile station and the second mobile communication network in the first mobile communication network when the mobile station operates in the first mobile communication network; transmitting information necessary for calculating the second cipher key from the first mobile communication network to the mobile station when the mobile station operates in the first mobile communication network; calculating the second cipher key at the mobile station to be used for ciphering traffic between the mobile station and the second mobile communication network; transmitting the second cipher key from the first mobile communication network to the second mobile communication network; transmitting the second cipher key calculated at the mobile station to a ciphering module of the mobile station in response to a request from the first mobile communication network to handover to the second mobile communication network; and ciphering traffic between the mobile station and the second mobile communication network using the second cipher key after handover is complete.