【精选】10-WLAN和GSM3G安全10-WLAN和GSM3G安全.pptVIP

安全协议与标准 linfb@sdu.edu.cn 2009, 11 ToC WLAN GSM 3G WLAN 802.1x 802.11i 802.11-1997 (802.11 legacy) 802.11a-1999 802.11b-1999 802.11g-2003 802.11-2007 802.11n WLAN channels 2.4Ghz 802.1X IEEE 802.1X is an IEEE Standard for port-based Network Access Control (port meaning a single point of attachment to the LAN infrastructure). It is part of the IEEE 802.1 group of networking protocols. It provides an authentication mechanism to devices wishing to attach to a LAN, either establishing a point-to-point connection or preventing it if authentication fails. It is used for most wireless 802.11 access points and is based on the Extensible Authentication Protocol (EAP). 802.11i The 802.11i architecture contains the following components: 802.1X for authentication (entailing the use of EAP and an authentication server), RSN for keeping track of associations, and AES-based CCMP to provide confidentiality, integrity, and origin authentication. Another important element of the authentication process is the four-way handshake. The Four-Way Handshake WEP: Wired Equivalent Privacy WPA: 802.11i / Wi-Fi Protected Access WPA implemented a subset of 802.11i WPA2: 802.11i-2004/WPA2 WAPI: WLAN Authentication and Privacy Infrastructure GSM结构 GSM 频段和信道使用 900＋M、1800Mhz，AMPS 800＋M 先FDM，再TDM 124对上/下行子信道宽200khz，总124×8＝992个连接 子信道使用 用户数据片57×2＝114b 令加3＋57＋1＋26＋1＋57＋3＝148b 头尾3b0，26b同步信息，1＋1b类型标志（语音/数据） TDM帧含由8个用户数据 148×8＝1184b＋8.25×8（隔离）＝1250b 多帧 26个TDM帧（时隙）组成1个多帧 1250×26＝32500b 对应120ms的传输时间 合9.6kbps GSM was designed with a moderate level of service security. The system was designed to authenticate the subscriber using a pre-shared key and challenge-response. Communications between the subscriber and the base station can be encrypted. GSM安全 密钥Ki和Kc 算法A3、A8和A5 AUC发出16B随机数R，SIM卡使用A3算法从Ki和R计算应答值Res以及64b加密钥Kc，Kc被手机A5算法用以加密数据。 A3/A8/A5 用户身份由SIM卡中的IMSI唯一标识(漫游过程中使用临时性的TMSI)，SIM卡中还有用户认证密钥Ki(这个密钥在AUC有拷贝)和认证算法A3和加密密钥产生算法A8，移动台MS(就是手机)中有加密算法A5。 A3是典型的挑战-应答机制 ，AUC使用随机数挑战用户，该随机数也参与A8产生加密密钥Kc。 A5/1 and A