Abstract: A mechanism is presented for reasoning about belief as a systematic way to understand the working of cryptographic protocols. The mechanism captures more features of such protocols than that given by M. Burrows et al. (1989) to which the proposals are a substantial extension. The notion of possession incorporated in the approach assumes that principles can include in messages data they do not believe in, but merely possess. This also enables conclusions such as 'Q possesses the shared key', as in an example to be derived. The approach places a strong emphasis on the separation between the content and the meaning of messages. This can increase consistency in the analysis and, more importantly, introduce the ability to reason at more than one level. The final position in a given run will depend on the level of mutual trust of the specified principles participating in that run. >

Abstract: A two par ty protocol in which par ty A uses one of several secret witnesses to an NP assertion is witness indistinguishable if par ty B cannot tell which witness A is actually using. The protocol is witness hiding if by the end of the protocol B cannot compute any new witness which he did not know before the protocol began. Witness hiding is a natural security requirement, and can replace zero knowledge in many cryptographic protocols. We prove two central results: 1. Unlike zero knowledge protocols, witness indistinguishablity is preserved under arbi t rary composition of protocols, including parallel execution. 2. If a s ta tement has at least two independent witnesses, then any witness indistinguishable protocol for this s ta tement is also

Abstract: A computer network has a number of computers coupled thereto at distinct nodes. A trust realm table defines which computers are members of predefined trust realms. All the members of each predefined trust realm enforce a common set of security protocols for protecting the confidentiality of data. Each computer that is a member of a trust realm enforces a predefined security policy, and also defines a security level for each set of data stored in the computer. Thus, each message has an associated label denoting how to enforce the computer's security policy with respect to the message. A trust realm service program prepares a specified message for transmission to a specified other computer system. To do this it uses the trust realm table to verify that both the computer system and the specified computer system are members of at least one common trust realm, and then selects one of those common trust realms. The message is transmitted as a protocol data unit, which includes a sealed version of the message, authenticated identifiers for the sending system and user, the message's label, and an identifier for the selected trust realm. Received protocol data units are processed by validating each of the components of the received protocol data unit before accepting the sealed message in the protocol data unit as authentic. Further, the label in the received protocol data unit is used by the receiving computer to determine what predefined security policy is to be enforced with respect to the message.

Abstract: The author adapts a knowledge-oriented model of distributed systems in order to analyze cryptographic protocols. This new model provides semantics for a logic of knowledge, time and communication. He expresses and proves with this logic security properties as secrecy and authentication. >

Abstract: This paper provides an application of game theoretic techniques to the analysis of a class of multiparty cryptographic protocols for secret bit exchange.

Abstract: A requested cryptographic function is validated for performance in conjunction with a cryptographic key, by inputting a first portion of an associated control vector into a first control vector checker, which outputs a first authorization signal if the requested cryptographic function has been authorized by the originator of the key. A second portion of the control vector is input to a second control vector checker, which outputs a second authorization signal if the requested cryptographic function has been authorized by the originator of the key. Both the first and the second authorization signals are applied to a cryptographic processor which initiates the execution of the requested cryptographic function.

Abstract: It is shown that some well known cryptographic protocols for authentication are insecure if the underlying cryptographic algorithm does not avoid certain special features. Explicit assumptions based on the fundamental properties of cryptographic transformations are recommended as a basis for cryptographic protocol design. It is shown how these properties may be used to design alternative forms of the protocols analysed.

Abstract: A logic and associated formal semantics specifically designed to represent and analyze cryptographic protocols are presented. A language is given with distinct means to represent knowledge of an individual word (e.g., the ability to recognize or produce a decryption key) and propositional knowledge. A sample analysis of a protocol is given to demonstrate the potential usefulness of the system. >

Abstract: The author introduces a form of attack, a verifiable-test attack, in which an attacker obtains secret information, such as a password used in a protocol, without breaking the underlying cryptosystem. An investigation is made of the essence of a verifiable-text attack, and an algorithm for examining protocols and searching for vulnerabilities to such an attack is developed. Caution has to be exercised in certifying that a protocol is not vulnerable because a healthy protocol may become vulnerable when it interacts with another vulnerable or even healthy protocol. >

Abstract: In a process for the cryptographic processing of data in a cryptographic system, processing takes place in two parts In the first part the data transmission routines within a data entity and a coded text entity are detected The clear text and the cryptographic are separately processed cryptographically in the second part and then recombined in the first part with the data transmission routines

Abstract: The purpose of key management is to provide procedures for handling cryptographic keying material to be used in symmetric or asymmetric cryptographic mechanisms. As a result of varied design decisions appropriate to different conditions, a large variety of key distribution protocols exist. There is a need to explicate key distribution protocols in a way that allows to understand which results they achieve and on which assumptions they depend. We define a modular system that can be used to transform cryptographic protocols into a generic form and that has proven to be useful in the analysis and the construction of such protocols.

Abstract: The first aim of this paper is to situate the call for integrity and authentication algorithms within research on cryptography and within evolution of telecommunication. Motivations for submitting primitives and details on the submission process are also given.

Abstract: A soft logic cryptographic circuit (10) that can be reprogrammed with various cipher algorithms. The cryptographic circuit is comprised of at least one cryptographic core device (100, 101), comprising means for storing and executing a cipher algorithm and for storing digital information (106-116); reprogrammable supervisory means (102), operably associated with the at least one cryptographic core device (100, 101) for utilizing cipher algorithm storage instructions to control the storing of the cipher algorithm in the at least one cryptographic core device (100, 101) and for utilizing cipher algorithm execution instructions to control the execution of the cipher algorithm by the at least one cryptographic core device (10); and, input/output means (103), operably coupled to the at least one cryptographic core device (100, 101) and the reprogrammable supervisory means (102) for utilizing digital information storage instructions to control the storing of the digital information of the at least one cryptographic core device (100, 101) and for providing digital communication paths (104) from the cryptographic circuit (10).

Abstract: Secure distributed systems are not easily constructed, as they combine mechanisms based on very different theories of security (encryption and reference monitors). The authors show how these mechanisms may be integrated via the Unix STREAMS mechanism Examples are given of how this architecture can support existing security protocols and it is shown why it is consistent with the Bell-LaPadula and Biba information-flow models. >

Abstract: In a cryptographic protocol, it is important for a recipient to determine that a message has not been modified during transmission. This is normally achieved by providing redundancy in the message. Typically, a message is described in the literature as containing enough redundancy, not enough redundancy, or no redundancy at all. This note shows that, because of the secrecy that comes with encryption, redundancy can be provided at two different levels. An example demonstrates that this distinction is useful in guarding against certain cryptographic attacks on weak keys.

Abstract: A secure data exchange (SDE) protocol to provide data confidentiality for secure data communication between two authorized end user systems in an IEEE 802 Local Area Network (LAN) environment is presented. In the development of this protocol, the various primitives used and parameters included in them are given. Also, the secure transmission and reception of these primitives between peer layer entities of source and destination end user systems are presented to achieve data confidentiality security service. >

Abstract: A protocol usually refers to customs and regulations dealing with diplomatic formality, precedence and etiquette. Typically, a protocol determines a map for seating the participants, or the order of speeches. It has happened that an international conference has spent most of the time while arguing about the seating protocol.

Abstract: A two-party cryptographic protocol for evaluating any binary gate is presented. It is more efficient than previous two-party computations, and can even perform single-party (i.e. satisfiability) proofs more efficiently than known techniques. As in all earlier multiparty computations and satisfiability protocols, commitments are a fundamental building block. Each party in our approach encodes a single input bit as 2 bit commitments. These are then combined to form 5 bit commitments, which are permuted, and can then be opened to reveal the output of the gate.

Abstract: We present some practical security protocols that use private-key encryption in the public-key style. Our system combines a new notion of private-key certificates, a simple key-translation protocol, and key-distribution. These certificates can be administered and used much as public-key certificates are, so that users can communicate securely while sharing neither an encryption key nor a network connection.

Abstract: To obtain security, one needs to utilize many resources Among these are one-way functions, physically secure communication channels, and —though less well known— broadcasting