Relationships among security and algebraic properties of cryptographic objects, and a security infrastructure for agent communication languages

Modern cryptographic objects are used in solving an ever-growing, increasingly diverse set of problems such as authentication, digital signatures, and privacy. Our research applies such objects in novel protocols for secret-key agreement and digital signatures and in a new security infrastructure for agent communication languages.

In Part I of this dissertation, we explore relationships among algebraic and security properties of cryptographic objects. Based on ideas proposed by Sherman, we start by combining associativity and one-wayness to define associative one-way functions (AOWFs). We prove that partial AOWFs exist if and only if $P\ne NP$. Moreover, we present protocols that apply strong AOWFs to achieve unauthenticated secret-key agreement and digital signatures.


n Part II, Despite security and privacy concerns agents might encounter whenever they cross multiple administrative domains, agent communication languages standards lack the necessary constructs that enable secure cooperation among software agents. We propose Secure Knowledge Query Manipulation Language (SKQML) as a security infrastructure for KQML-speaking agents. SKQML enables KQML-speaking agents to authenticate one another, implement specific security policies based on authorization methods, and whenever needed to ensure the privacy and confidentiality of the messages exchanged. SKQML is simple, extensible, and at a level appropriate for intelligent communicating agents. Moreover, SKQML provides security mechanisms as an integral part of the communication language. We give details of the synthesis of public key certificate standards and agent communication languages to construct an infrastructure that meets the security needs of cooperating agents. We introduce three new performatives that facilitate the implementation of the security policies of agents. In addition, we define a propositional security language that is based on public key certificate standards and we introduce new protocols for trust management with detailed examples using a partial prototype implementation of this infrastructure.

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agent communication, cryptography, skqml


University of Maryland, Baltimore County

Computer Science and Electrical Engineering


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