الفهرس 
Introduction and AimOnly 14 pages are availabe for public view
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Abstract
The Asynchronous Transfer Mode (ATM) forum introduced the ATM security specifications version 1.1 in year 2001 aiming to protect data transmission over ATM networks. Many drawbacks have been noticed in these specifications which are considered as an advanced work in the ATM security research field.
In this thesis, an introduction to the techniques being implemented in the ATM protocol is discussed and the structure of the data unit (cell) in the ATM protocol is described. In addition the function of each field is demonstrated.
The required security services in any ATM network and the possible attacks that may affect the ATM networks are emphasized. The techniques being followed for generating, exchanging and updating session keys according to ATM security specifications version 1.1 is introduced.
The ATM security specifications version 1.1 could be further improved if digital signature algorithm (DSA) is supported by the end user of the ATM network. In this case, there are many drawbacks which summarized and discussed in details in this thesis.
A modified mechanism for session key update in DSA-Supporting ATM networks is then introduced to solve the discussed drawbacks. The modified mechanism is flexible and can be modified by users or by network manager to achieve better security results.
The suggested technique allows the next session key number or the lifetime of the current session key to be unpredicted. The modified mechanism for session keys update in ATM networks supporting DSA at the end users enable individuals to achieve more secure communications over the network. This achievement can be employed without affecting the quality of service (QoS) introduced by the ATM protocol.