由於無線網路群播服務的特性，在不同時段群組成員人數的差異可能會很大，所以無線網路群播服務金鑰管理機制必須提供有效率的群組成員增加及縮減的方法，以減低系統進行Re-Keying作業時網路的負載，此外，方法設計上需儘量減低行動處理機本身在產生新KEK Keys的負荷，降低無線網路群播服務行動處理機的使用門檻，及增加行動處理機使用的時間。
先前的研究，以集合為單位來進行Re-Keying訊息的傳送曾在Boolean Function Minimization 及EBS文章中提出，前者以Binary -k-Cube為基礎，結合布林函數化簡的想法，提出整批(Batch)作業Re-Keying的機制；而EBS則多數在探討針對單一使用者之Re-Keying機制，雖然EBS進行Re-Keying所造成的網路負載要比Tree-based的方法少，但是EBS由於本身設計的限制，群組成員的縮減及擴增必需重新選定每人手上持有的KEK數量(即重新選定k與m值)及其值，運作上有其困難，且作者並無提出明確的解決方法，如果群組人數差異很大，會造成系統資源很大的浪費。
我們在本研究中則採用Binary-k-Cube的概念加以延伸，除了說明Binary-k-Cube用在非整批作業的Re-Keying方法外，也提出Binary-k-Cube機制如何讓系統縮減及擴增的方法。此外，我們也提出了XOR的運算方法，來取代之前所使用的One Way Hash運算，得出新的KEK Keys值，減低行動處理機的負荷。

The number of group members in a wireless multicast service may be varying widely over the operation time. Therefore, an efficient mechanism for adapting to the change in the group members must be in place for reducing wireless network overheads in a secure multicast key management scheme. Besides, the mechanism must consider mobile hosts capacity for reducing computing overhead in regenerating new KEK keys.
In both the Boolean Function Minimization and the EBS methods, KDC gives each member a set of KEK Keys from the key pool for securing group communication. Each KEK key forms a set, because the KEK key is the same in some group members. KDC can send Re-Keying messages that is based on each set. The Boolean Function Minimization approach focuses on batch Re-Keying system when many group members leave the communication group at the same time. It uses Binary-k-Cube concept along with the Boolean function minimization techniques. The EBS method addresses the common Re-Keying system that considers the case of having a single group member leave the communication group. But it has difficulty of adapting to the change of group size in EBS, even though EBS is better than Tree-based method on Re-Keying overhead in the network. So, EBS wastes system resources when the range of group size varies widely.
In this thesis, we extend the Binary-k-Cube technique to cope with non-batch Re-Keying Systems. We design a simple method to adjust the amount of KEK keys for each member when the group members are changed. Besides, we use the XOR technique to replace One Way Hash Functions to generate new KEK Keys for old group members so as to minimize the computational overheads.

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