26 May 2016

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.


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.


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.

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