Abstract:

The strand space model to analyze guessing attack on the authenticated protocol based on passwords was proposed. The penetrator’s strands were extended through adding guessing traces and the types of cryptographical operation. A new notion of ideal was defined and relative theorems were therefore modified and proved. The extended honest ideal model not only inherits its original characters, but also is adaptive for the analysis of guessing attack. The GLNS protocol was utilized to illuminate how to analyze a protocol formally and effectively by the use of this extended strand spaces.

Key words: security protocol, guessing attack, strand space, honest ideal