Generic Architecture and Semiconductor Intellectual Property Cores for Avanced Encryption Standard Cryptography

A generic architecture for implementing the advanced encryption standard (AES) encryption algorithm in silicon is proposed. This allows the instantiation of a wide range of chip specifications, with these taking the form of semiconductor intellectual property (IP) cores. Cores implemented from this architecture can perform both encryption and decryption and support four modes of operation: (i) electronic codebook mode; (ii) output feedback mode; (iii) cipher block chaining mode; and (iv) ciphertext feedback mode. Chip designs can also be generated to cover all three AES key lengths, namely 128 bits, 192 bits and 256 bits. On-the-fly generation of the round keys required during decryption is also possible. The general, flexible and multi-functional nature of the approach described contrasts with previous designs which, to date, have been focused on specific implementations. The presented ideas are demonstrated by implementation in FPGA technology. However, the architecture and IP cores derived from this are easily migratable to other silicon technologies including ASIC and PLD and are capable of covering a wide range of modem communication systems cryptographic requirements. Moreover, the designs produced have a gate count and throughput comparable with or better than the previous one-off solutions.

Philosophers and practical men: Charles Babbage, Irish merchants and the economics of information

Before the emergence of coordination of production by firms, manufacturers and merchants traded in markets with asymmetric information. Evidence suggests that the practical knowledge thus gained by these agents was well in advance of contemporary political economists and anticipates twentieth-century developments in the economics of information. Charles Babbage, who regarded merchants and manufacturers as the chief sources of reliable economic data, drew on this knowledge as revealed in the evidence of manufacturers and merchants presented to House of Commons select committees to make an important pioneering contribution to the theory of production and exchange with information asymmetries.

PVT Property Measurements for Some Aliphatic Esters from (298 to 393) K and up to 35 MPa

The results of PVT measurements of the liquid phase within the temperature range of (298 to 393) K and up to 35 MPa are presented for some aliphatic esters. Measurements were made by means of a vibrating-tube densimeter, model DMA 512P from Anton Parr. The calibration of the densimeter was performed with water and n-heptane as reference fluids. The experimental PVT data have been correlated by a Tait equation. This equation gives excellent results when used to predict the density of the esters using the method proposed by Thomson et al. (AIChE J. 1982, 28, 671-676). Isothermal compressibilities, isobaric expansivities, thermal pressure coefficients, and changes in the isobaric heat capacity have been calculated from the volumetric data.

Structure and Change: Douglass North's Economics

Douglass North is a pivotal figure in the development of the 'new' economic history as well as the 'new' institutional economics. However, the relationship between these two aspects of his thinking remains undeveloped in previous critical assessments of North's work. The relationship is clarified here. The evidence presented indicates that three distinct phases can be distinguished in his writings between the 1950s and the 2000s. The paper relates these changing views to the shifting mainstream within economics and the effects that this shift has in turn had on economic history research. Economic history has adapted to economic research by abandoning some practices associated with the earlier cliometric literature. Furthermore, North is unique to the extent that his recent writings represent something of a convergence with 'old' institutionalism. © 2010 Taylor & Francis.

Value-oriented impact assessment: the economics of a new approach to impact assessment

Environmental Impact Assessment has gained a prominent position as a tool to evaluate the environmental effects of economic activities. However, all approaches proposed so far use a burden-oriented logic. They concentrate on the different environmental impacts in order to ascertain the overall environmental damage caused by economic activity. This paper argues that such a burden-oriented view is (a) hampered by a series of methodological shortcomings which hinders its widespread use in practice; and (b) is analytically incomplete. The paper proposes a value-oriented approach to impact assessment. For this purpose an economic analysis of the optimal use of environmental and social resources is conducted from both a burden-oriented and a value-oriented standpoint. The basic logic of a value-oriented impact assessment is explained, as well as the resulting economic conditions for an optimal use of resources. In addition, it is shown that value- and burden-oriented approaches are complementary to achieve optimality. Finally, the paper discusses the conditions under which the use of burden- or value-oriented impact assessments is appropriate, respectively.