Lecture 4

• Lecture 4: Logics and Models for Reasoning about Authentication .
• Plan for Today, Part I .
• Goals for Today .
• Taxonomy of Approaches .
• Assumptions .
• Intuitively .
• Basic Notation .
• BAN Constructs (I) .
• BAN Constructs (II) .
• BAN Constructs (III) .
• BAN Rules (I): Message-Meaning Rules .
• BAN Rules (II) .
• BAN Rules (III): Message Rules .
• BAN Rules (IV): Sees Rules .
• BAN Rules (V): Freshness Rule .
• BAN Rules (VI): Other Rules .
• Idealized Protocols .
• Using the BAN Logic .
• Authentication Goals .
• Otway -Rees [1987] .
• Otway -Rees Idealized .
• Assumptions .
• Otway -Rees Analysis .
• What BAN Say We Learn From the Analysis .
• Needham -Schroeder [1978] .
• Idealized Needham -Schroeder .
• Assumptions .
• Analysis of Idealized Needham -Schroeder .
• What We Learn From Analysis .
• Summary of BAN Analyses .
• BAN Criticisms .
• Other Logics .
• Models for Reasoning About Authentication, Part II .
• Goals for Today .
• Taxonomy of Approaches .
• Dolev - Yao Overview .
• Public Key Encryption Review .
• Example 1 .
• Breaking Example 1 .
• Example 2 (variation of Needham -Schroeder) .
• Example 3: Extra encryption is not always a good idea. .
• Breaking Example 3 .
• Summary of Dolev - Yao Results .
• Cascade Protocols .
• Example .
• Definition of Secure (Cascade Protocol) .
• Example 1 Again .
• Name-Stamp Protocols .
• Restriction .
• Definition of Secure (Name-Stamp Protocol) .
• Example 2 again .
• Example 3 again ( normal ) .
• Breaking Example 3 .
• Breaking Example 3 .
• Breaking Example 3 (parsed) .
• Abadi -Tuttle Overview .
• Model of Computation .
• Runs .
• State Variables .
• Set of Actions Per Principal .
• Auxiliary State Information .
• Syntactic Restrictions on Runs .
• Semantics to Logic .
• Semantics (I) .
• Semantics (II) .
• Semantics (III) .
• Possible Worlds Semantics .
• Knowledge vs . Belief .
• Knowledge vs . Belief .
• Possible Worlds Semantics For Belief Logics .
• Semantics (IV) .
• Other Models .
• Other Models ( cont'd ) .
• Summary of Analysis Methods for Authentication .
• Next Lecture .

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Heather L. Marko
Last Modified: October 1998