Basic Cryptography

          

Does increased security provide comfort to paranoid people? Or does security provide some very basic protections that we are naive to believe that we don't need? During this time when the internet provides essential communication between millions of people and is being increasingly used as a tool for commerce, security becomes tremendously important issue to deal with.There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting passwords. One essential aspect for secure communication is cryptography.

Cryptography is the practice and study of techniques for secure communication in the presence of third parties. More generally, it is about constructing and analysing that overcome the influence of third parties.In layman's terms it is a science of coding and decoding of messages so as to keep these messages secure and not let it fall in the hand of unauthorised people. Also cryptography is used to store data and retrieve it back safely.

CLASSIC CRYPTOGRAPHY

The main classical cipher(an algorithm for performing encryption or decryption) types are transposition ciphers, which rearrange the order letters in a message and substitution ciphers,which symmetrically replace letters with other letters.

Example: "Hello world" becomes "ehlol owrdl" in a trivially simple rearrangement scheme.

MODERN CRYPTOGRAPHY 

The development of digital computers and electronics after the WWII made possible much more complex ciphers. Furthermore, computers allowed for the encryption of any kind of data representable in any binary format, unlike classic ciphers which only encrypted written language texts.

         German Lorenz cipher machine used in WWII to encrypt very high level staff messages

These days a fine example of cryptography is credit card with smart card capabilities. Smart cards combine low cost and portability with the power to compute cryptographic algorithms.

The padlock icon from a web browser, meant to indicate a page has been sent in encrypted-protected form. However, seeing an icon results when code is intended to render it.

A very simple example which all of us use in our daily life is the email.
We live in a modern world. We must deliver emails either for business, to friends, companies, famous people who's address we have. It doesn't matter. We send emails all the time. People deliver 210 billion emails daily! When you deliver an email, it has to get through the internet. A lot of people like to steal data from others, sometimes only for fun but danger comes when it is for something else. The internet is a BIG world. Emails are protected using data encryption. PGP(Pretty Good Privacy) is one method of protecting the email. This is both the name of a computer program and the protocol itself. So what exactly is the PGP protocol? It is a method to secure emails, a standard in cryptographically secure emails.

Hence by using of encryption techniques a fair unit of confidentiality, authentication, integrity, access control and availability of data is maintained.

AR and VR: The Future is Here

http://www.theverge.com/2015/1/21/7868251/microsoft
-hololens-hologram-hands-on-experience

Introduction

Initially, early man was left in this world to fend for himself. In the mission of survival, many changes and innovations were brought about. Over the years the factors which lead to change kept on changing but the rate of innovation only accelerated. In the 20th century people could only dream about having a TV, Radio, Calculator, etc.. in their pocket. This was made a reality in the beginning of the 21th century with the introduction of smartphones. Smartphones have changed our lives in many aspects. It is estimated that a major innovation is brought about within every 20 years. This leads us to an important question: What is the next big thing?

Smartphones have changed the way we communicate and get information. Many people believe that the next big thing will change what we perceive as reality. It should be able to let us go into a digital world where we can not only get spontaneous information but also experience various situations. Seeing potential in this world, many people started working on it. Their result: Virtual Reality(VR) and Augmented reality(AR).

Virtual Reality(VR)

Virtual reality refers to immersive multimedia which can expose the user to the virtual world and make him/her believe that that is the real environment.

It is made interactive by engaging all the senses of the user. So you could basically be the real-life Marvel hero, Tony Stark.

Picture this, a world with rockets, books, icecreams or even a choco land. Mouth watering isn't it? Well you could experience it right now. Just get yourself a google cardboard for ₹650 and you’ll be on your way.

http://www.popsci.com/google-cardboard

VR Headsets give us an experience of virtual reality. A lot of them are available in the market. As a beginner, you could get yourself a google cardboard for a very cheap price. For better performance you can consider Oculus rift, HTC Vive and Samsung Gear VR.

Uses of VR

https://www.kickstarter.com/projects/1523379957/
oculus-rift-step-into-the-game/posts/872324

Virtual reality lets you experience various things before we actually do it in the real world. Imagine playing a first person shooting game like call of duty directly on the battle ground. Imagine paying a visit to Paris while sitting at home. Imagine experiencing various emergency situations before they actually happen in reality. Intriguing isn’t it? Well, VR has turned all these dreams into a reality.

Virtual Reality takes you away from the real world and lets you interact with the virtual world. A few other people thought differently. They started working on what we call today, Augmented Reality(AR).

Augmented Reality(AR)

Augmented reality refers to the integration of digital information with the environment that we live in. It can be used to satisfy the ever growing thirst for information that we as humans have.

http://www.pcmag.com/article2/0,2817,2416488,00.asp

http://www.newstatesman.com/sci-tech/2015/06/how-
microsofts-breakthrough-portable-
holographic-technology-could-make-science

Google glass and Microsoft Hololens are the best examples for augmented reality. Google glass provides a lot of information on the go. The Microsoft Hololens works a bit differently, It combines the elements of VR and AR. It displays the elements of the virtual world in our environment.

For more information on Microsoft Hololens, check out, http://kumaranhmd.blogspot.in/2015/02/the-microsoft-hololens.html

Future of AR

AR has a lot of potential as it can mobilise information easily to masses.

It can be used to make interactive user manuals with real time instructions, improve sightseeing by displaying information on just viewing the object, provide navigation by overlaying routes on the user’s plane of sight, play immersive games and help consumers to visualise products as a part of their environment.

Conclusion

The pace of technological evolution is high and it will only increase in the future. AR and VR are just one of the many technological innovations out there. But one thing is for certain, they are here to stay. We might one day live in a desired virtual world where all of us can live virtually anywhere in complete freedom. It also has the potential to make every object, surface and environment a portal to the digital world, full of information. That day is not far away. So let the virtual era begin!

https://www.youtube.com/watch?v=09vxKN1zLNI

ASCII : Alphabets in Computers

 ASCII : Alphabets in Computers

The storage of numbers is relatively easy to understand as, computers are very simple at the basic level. Computers use Base - 2, meaning they count in powers of two. This also means that computers have only Humans on the other hand count in Base - 10, meaning we  two digits, namely 0 & 1. Humans count in the powers of 10, so we have 10 digits (0-9). For example,

32 = 3 x 10^1  +2 x 10^0 ("^" means raised to the power of)

For computers,

32 = 1 x 2^5 + 0 x 2^ 4 + 0 x 2^3 + 0 x 2^2 + 0 x 2^1 + 0 x 2^0

Each 2^x represents a "bit". Think of each bit as a slot. In this slot a zero or one can be placed. The bits are also represented as powers of two in their order. For example : the fourth bit is 0 or 1 into 2^4. Nowadays, computers have either 32 bits or 64 bits meaning the maximum value that can be stored is 2,147,483,647. Note : we can DISPLAY numbers greater than this. But on a 32 bit computer, this is the maximum value you can STORE.

So, if every possible configuration of the bits (slots) is used up to represent unique numbers, where is the place for letters? Computers need to be able to process letters for being useful to us, otherwise, the are just expensive calculators.

Here is where ASCII comes in. ASCII stands for  American Standard Code for Information Interchange. ASCII helps us to store and display letters on our screens.

In the ASCII encoding (fancy term for saying configuration of letters), a letter is given a unique numerical value. When the computer receives this value, it processes it as a letter. The value of "a" is given a value of 97. Note : "a" is different from "A" as they are considered as different characters.

You must be wondering, if every possible binary value is represented as a number, and each letter is represented by a number, how does a computer know weather we mean "a" or just 97?

Actually, your computer doesn't .

In reality, your computer is just hardware. What makes it really run is your operating system or software. The Operating System is the main piece of software. Windows, OSX and Linux are all operating systems. Now if you open your web-browser like Chrome or IE (Why do you still use this?) you are running another piece of software on top of your operating system.

Think of it as a cake  : Your hardware is the base, your operating system is like frosting and applications are like the cherry on top.

So, when you press the KEY on your keyboard, your operating system identifies it either as a number or a letter, while your HARDWARE processes it as a number/alphabet. In this way computers can identify numbers and letters uniquely and helps you type. 

When you open notepad, you can be sure that whatever you want to write actually happens.

-Raghav M

The Beginning of Digital Data: Compact Discs(CD)

CD discs are now on the brink of being removed from the digital world. The Macbook Pro, released by Apple,  doesn't even have a CD slot. The new pen drives and hard drives are taking the place of the Compact Discs.

Compact Discs are important from a beginners point of view as they were one of the first means of storing large amounts of digital data. Until then data was stored in an analog way. Digital data is usually represented in bits. On and off signals are generally used to relay messages. Analog data, however, is transmitted by using changes in amplitude, frequency or an other property in proportion to that of a variable.

CDs initially could store 650 Mb of data, a far cry from today's terabyte storing hard drives. Nevertheless in their time CDs were very important. A CD works with a very important concept called Optic Laser Technology. A CD is initially a flat disc. A machine in a factory uses a "write laser" to carve out certain patterns on the CD discs. The patterns are in the form of "pits" and "lands".

These "pits" and "lands" themselves do not represent "1" and "0" but rather a change from pit to land or land to pit is read as one, but no change is read as zero. The write laser as mentioned above is quite powerful and is used to write or "burn" information onto the CD's polycarbonate layer in the form of pits and burns.



Reading the CD is also a similar process. Another laser known as the "read laser" moves across the CD in a spiral fashion. The CD reader also includes a photo cell or a diode which detects light by changing its resistance based on the light received(for more information on photocells: http://www.instructables.com/id/Photocell-tutorial/). As the laser moves on the disc different readings emerge. When the laser encounters a land the light is reflected normally and the photocell receives the light and sends a signal to the microcontroller transmitting the binary digit "1". If a pit is encountered the light is scattered and no data is light is received by the photocell and hence it transmits the binary digit "0". Like this a series of  "1" and "0" are transmitted. This is later used by the computer.



CDs at first to a layman might seem as an ordinary electric component, but the brains,ingenuity, and precision must be applauded. Though CDs will cease to exist in another few years the spark they have created in the realm of storing massive digital data is worth recognising.