vii Part 1. ULTIMATE PHYSICAL LIMITS IN ELEcrRONIC CCM1UNICATION Breaking the Recursive Bottleneck Professor David G. Messerschmitt 3 Optimum Scales and Limits of Integration Professor Daniel V. McCaughan . . . . 21 On Ultimate Thermodynamic Limitations in Communication and canputation Professor Jerome Rothstein 43 Part 2. STATISTICAL, INFORMATIONAL, COMPUTATIONAL AND CRYPI'OGRAPHIC LIMITS On the Capacity of Peak Power Constrained Gaussian Channels Professor I. Bar-David .. . . . . . . . . . .... 61 Complexity Issues for Public Key Cryptography Professor Ian F. Blake, Dr. Paul C. van Oorschot and Dr. Scott A. Vanstone . . .. . . .. .. . . 75 Collaborative Coding for Optical Fibre Multi-User Channels Dr. P. Bridge . ... . .... . . . .. 99 What Happened with Knapsack Cryptographic Schemes? Professor Y. G. Desmedt . ... . . . ..... 113 Optical Logic for Computers Dr. Robert W. Keyes . . . . 135 Limitations of Queueing Models in Communication Networks 143 Professor Anthony Ephremides . . . . . . . . . . . . Limits to Network Reliability Dr. GUnter G. Weber . .. . . 155 Two Non-Standard Paradigms for Computation: Analog Machines and Cellular Automata Professor Kenneth Steiglitz ........ 173 The Capacity Region of the Binary Multiplying Channel - A Converse Professor J. Pieter M. Schalkwijk . . . . . . . .. . 193 Recent Developments in Cryptography Dr. Fred Piper . . . . . . . . 207 vi The Role of Feedback in Communication Professor Thomas M. Cover . . . . . . 225 The Complexities of Information Transfer with Reference to a Genetic Code Model Mr. G. A. Karpel . . .. . . . . . . . .