Definition
The subject of quantum computing brings together ideas from classical information theory, computer science, and quantum physics. This document aims to summarize not just quantum computing, but the whole subject of quantum information theory. It turns out that information theory and quantum mechanics fit together very well. In order to explain their relationship, the paper begins with an introduction to classical information theory .The principles of quantum mechanics are then outlined.
The EPR-Bell correlation and quantum entanglement in general, form the essential new ingredient, which distinguishes quantum from classical information theory, and, arguably, quantum from classical physics. Basic quantum information ideas are described, including key distribution, teleportation, the universal quantum computer and quantum algorithms. The common theme of all these ideas is the use of quantum entanglement as a computational resource.
Experimental methods for small quantum processors are briefly sketched, concentrating on ion traps, super conducting cavities, Nuclear magnetic resonance imaging based techniques, and quantum dots. "Where a calculator on the Eniac is equipped with 18000 vacuum tubes and weighs 30 tons, computers in the future may have only 1000 tubes and weigh only 1 1/2 tons" Popular Mechanics, March 1949.
Now, if this seems like a joke, wait a second. "Tomorrows computer might well resemble a jug of water"
This for sure is no joke. Quantum computing is here. What was science fiction two decades back is a reality today and is the future of computing. The history of computer technology has involved a sequence of changes from one type of physical realization to another --- from gears to relays to valves to transistors to integrated circuits and so on. Quantum computing is the next logical advancement.
Today's advanced lithographic techniques can squeeze fraction of micron wide logic gates and wires onto the surface of silicon chips. Soon they will yield even smaller parts and inevitably reach a point where logic gates are so small that they are made out of only a handful of atoms. On the atomic scale matter obeys the rules of quantum mechanics, which are quite different from the classical rules that determine the properties of conventional logic gates. So if computers are to become smaller in the future, new, quantum technology must replace or supplement what we have now.
Quantum technology can offer much more than cramming more and more bits to silicon and multiplying the clock-speed of microprocessors. It can support entirely new kind of computation with qualitatively new algorithms based on quantum principles!
Definition
In this seminar ,is giving some basic concepts about smart cards. The physical and logical structure of the smart card and the corresponding security access control have been discussed in this seminar . It is believed that smart cards offer more security and confidentiality than the other kinds of information or transaction storage. Moreover, applications applied with smart card technologies are illustrated which demonstrate smart card is one of the best solutions to provide and enhance their system with security and integrity.
The seminar also covers the contactless type smart card briefly. Different kinds of scheme to organise and access of multiple application smart card are discussed. The first and second schemes are practical and workable on these days, and there is real applications developed using those models. For the third one, multiple independent applications in a single card, there is still a long way to go to make it becomes feasible because of several reasons.
At the end of the paper, an overview of the attack techniques on the smart card is discussed as well. Having those attacks does not mean that smart card is unsecure. It is important to realise that attacks against any secure systems are nothing new or unique. Any systems or technologies claiming 100% secure are irresponsible. The main consideration of determining whether a system is secure or not depends on whether the level of security can meet the requirement of the system.
The smart card is one of the latest additions to the world of information technology. Similar in size to today's plastic payment card, the smart card has a microprocessor or memory chip embedded in it that, when coupled with a reader, has the processing power to serve many different applications. As an access-control device, smart cards make personal and business data available only to the appropriate users. Another application provides users with the ability to make a purchase or exchange value. Smart cards provide data portability, security and convenience. Smart cards come in two varieties: memory and microprocessor.
Memory cards simply store data and can be viewed as a small floppy disk with optional security. A microprocessor card, on the other hand, can add, delete and manipulate information in its memory on the card. Similar to a miniature computer, a microprocessor card has an input/output port operating system and hard disk with built-in security features. On a fundamental level, microprocessor cards are similar to desktop computers. They have operating systems, they store data and applications, they compute and process information and they can be protected with sophisticated security tools. The self-containment of smart card makes it resistant to attack as it does not need to depend upon potentially vulnerable external resources. Because of this characteristic, smart cards are often used in different applications, which require strong security protection and authentication.
Definition
Have you ever thought of a buffer overflow attack ? It occurs through careless programming and due to patchy nature of the programs. Many C programs have buffer overflow vulnerabilities because the C language lacks array bounds checking, and the culture of C programmers encourages a performance-oriented style that avoids error checking where possible. Eg: gets and strcpy ( no bounds checking ). This paper presents a systematic solution to the persistent problem of buffer overflow attacks. Buffer overflow attack gained notoriety in 1988 as part of the Morris Worm
incident on the Internet. These problems are probably the result of careless programming, and could be corrected
by elementary testing or code reviews along the way.
THE ATTACK :- A (malicious) user finds the vulnerability in a highly privileged program and someone else implements a patch to that particular attack, on that privileged program. Fixes to buffer overflow attacks attempt to solve the problem at the source (the vulnerable program) instead of at the destination (the stack that is being overflowed).
StackGuard :- It is a simple compiler extension that limits the amount of damage that a buffer overflow attack can inflict on a program. The paper discusses the various intricacies to the problem and the implementation details of the Compiler extension 'Stack Guard '.
Stack Smashing Attack :- Buffer overflow attacks exploit a lack of bounds checking on the size of input being stored in a buffer array. The most common data structure to corrupt in this fashion is the stack, called a ``stack smashing attack'' .
StackGuard For Network Access :- The paper also discusses the impacts on network access to the 'Buffer Overflow Attack'.
StackGuard prevents changes to active return addresses by either :-
1. Detecting the change of the return address before the function returns, or
2. Completely preventing the write to the return address. MemGuard is a tool developed
to help debug optimistic specializations by locating code statements that change quasi-invariant
values.
STACKGUARD OVERHEAD
" Canary StackGuard Overhead
" MemGuard StackGuard Overhead
" StackGuard Macrobenchmarks
The paper presents the issues and their implications on the 'IT APPLICATIONS' and discusses the solutions through implementation details of 'Stack Guard'.
