Cryptography – Communication system using cryptography – Wireless communication
Reexamination Certificate
2005-03-22
2005-03-22
Sheikh, Ayaz (Department: 2136)
Cryptography
Communication system using cryptography
Wireless communication
C380S239000, C380S270000, C380S274000, C380S277000
Reexamination Certificate
active
06870932
ABSTRACT:
A received PDU is sequentially identified by an n-bit frame number (FN) and an m-bit hyper frame number (HFN), which are synchronously maintained on first and second stations. The second station determines an activation time at which a ciphering key change is to occur, and composes a security mode command that includes an identifying FN corresponding to the activation time, and x least-significant bits (LSBs) from the HFN of the identifying FN. The second station transmits the security mode command to the first station. The x LSBs contained in the security mode command enable the first station to resolve cyclical ambiguities of the identifying FN to properly construct an application time. The first station uses a first ciphering key to decrypt PDUs with FNs sequentially prior to the application time, and uses a second ciphering key to decrypt PDUs with FNs sequentially on or after the application time.
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Michell, S., et al, “State Based Key Hop Protocol: A Lightweight Security Protocol for Wireless Networks”, National Research Council of Canada, ACM, 2004, entire document.*
Walker, J., “802.11 Security Series, Part II: The Temporal Key Integrity Protocol (TKIP)”, Network Security Architect,Platform Networking Group, Intel Corp., 2002, entire document.*
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ETSI TS 125 322 v3.8.0 (Sep. 2001) Universal Mobile Telecommunications System (UMTS); Radio Link Control (RLC) protocol specification (3GPP TS 25.322 version 3.8.0 Release 1999).
ASUS Computer International
ASUSTeK Computer Inc.
Baum Ronald
Hsu Winston
Sheikh Ayaz
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