Abstract not found

ly, the remote procedure call problem, which an RPC protocol undertakes to solve, consists of emulating LPC using message passing. LPC has a number of "properties" -- a single procedure invocation results in exactly one execution of the procedure body, the result returned is reliably delivered to the invoker, and exceptions are raised if (and only if) an error occurs. Given a completely reliable communication environment, which never loses, duplicates, or reorders messages, and given client and server processes that never fail, RPC would be trivial to solve. The sender would merely package the invocation into one or more messages, and transmit these to the server. The server would unpack the data into local variables, perform the desired operation, and send back the result (or an indication of any exception that occurred) in a reply message. The challenge, then, is created by failures. Were it not for the possibility of process and machine crashes, an RPC protocol capable of overcomi...

The increasing use of internetworking protocols to connect administratively heterogeneous networks has raised the question of how an organization can control the flow of information across its network boundaries. One method for doing so is the use of visas, a cryptographic technique for authenticating and authorizing a flow of datagrams. This report presents and evaluates two visa protocols ---- one that requires distributed state information in gateways and one that uses additional encryption operations instead of distributed state. Applications for such visa protocols include access control, accounting and billing for packet transit, and network resource management. This technical report is based, in large part, upon a shorter paper [8]. We have extended the discussion of design issues and added an appendix describing a visa protocol using dual-key (public key) encryption. Key Words: Computer networks, network interconnection, network security, access control, authentication, crypt...

Quantum theory has found a new field of applications in the realm of information and computation during the recent years. This paper reviews how quantum physics allows information coding in classically unexpected and subtle nonlocal ways, as well as information processing with an efficiency largely surpassing that of the present and foreseeable classical computers. Some outstanding aspects of classical and quantum information theory will be addressed here. Quantum teleportation, dense coding, and quantum cryptography are discussed as a few samples of the impact of quanta in the transmission of information. Quantum logic gates and quantum algorithms are also discussed as instances of the improvement in information processing by a quantum computer. We provide finally some examples of current experimental

has been an obvious target for abuse. Wireless identification is a powerful capability, and RFID reveals both a physical object’s nature and location. Anyone can easily gain unauthorized access to RFID data because they don’t need a line of sight to gather it. For example,

We consider the problem of establishing jam-resistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop and analyze this algorithm within the framework of a new type of code, concurrent codes, which are those superimposed codes that allow efficient decoding. Finally, we propose the Universal Concurrent Code algorithm, and prove that it covers all possible concurrent codes, and give connections between its theory and that of monotone Boolean functions.

Traditionally, omnidirectional, radio frequency (RF) communication has been made resistant to jamming by the use of a secret key that is shared by the sender and receiver. There are no known methods for achieving jam resistance without that shared key. Unfortunately, wireless communication is now reaching a scale and a level of importance where such secret-key systems are becoming impractical. For example, the civilian side of the Global Positioning System (GPS) cannot use a shared secret, since that secret would have to be given to all 6.5 billion potential users, and so would no longer be secret. So civilian GPS cannot currently be protected from jamming. But the FAA has stated that the civilian airline industry will transition to using GPS for all navigational aids, even during landings. A terrorist with a simple jamming system could wreak havoc at a major airport. No existing system can solve this problem, and the problem itself has not even been widely discussed. The problem of keyless jam resistance is important. There is a great need for a system that can broadcast messages without any prior secret shared between the sender and receiver. We propose the first system for keyless jam resistance: the BBC algorithm. We describe the encoding, decoding, and broadcast algorithms. We then analyze it for expected resistance to jamming and error rates. We show that BBC can achieve the same level of jam resistance as traditional spread spectrum systems, at just under half the bit rate, and with no shared secret. Furthermore, a hybrid system can achieve the same average bit rate as traditional systems. I.

Routing mechanisms for inter-autonomous region communication require distribution of policy-sensitive information as well as algorithms that operate on such information. Without such Policy Routing mechanisms, it is not possible for interconnected regions to retain their autonomy in setting and enforcing policy while still achieving desired connectivity. This problem of interconnecting and navigating across autonomous regions is of inherent interest to the security community because the policies in question concern control of resource access and usage. Moreover, the security of the Policy Routing protocols themselves must be considered if they are to be applicable in sensitive environments. On the other hand, as usual, the security mechanisms take a toll in overall system complexity and performance. Most routing protocols, including proposed Policy Routing protocols [l], focus on environments where detection of an attack after it has taken place is sufficient. The purpose of this paper is to explore the design of Policy Routing mechanisms for sensitive environments where more aggressive preventative measures are mandated. In particular, we detail the design of four secure protocol versions that prevent abuse through cryptographic checks of data integrity. We analyse and compare these schemes in terms of their per-packet processing overhead. We conclude that preventative security is feasible, although the overhead cost is quite high. Consequently, it is critical that prevention-based schemes coexist with detection-based schemes. 1

this document, authentication will generally refer to the use of digital signatures, which play a function for digital documents similar to that played by handwritten signatures for printed documents: the signature is an unforgeable piece of data asserting that a named person wrote or otherwise agreed to the document to which the signature is attached. The recipient, as well as a third party, can verify both that the document did indeed originate from the person whose signature is attached and that the document has not been altered since it was signed. A secure digital signature system thus consists of two parts: a method of signing a document such that forgery is infeasible, and a method of verifying that a signature was actually generated by whomever it represents. Furthermore, secure digital signatures cannot be repudiated; i.e., the signer of a document cannot later disown it by claiming it was forged.

Distribution A, Approved for public release, distribution unlimited Abstract. We consider the problem of establishing jam-resistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop and analyze this algorithm within the framework of a new type of code, concurrent codes, which are those superimposed codes that allow efficient decoding. Finally, we propose the Universal Concurrent Code algorithm, and prove that it covers all possible concurrent codes, and give connections between its theory and that of monotone Boolean functions.