Cryptography |definition and uses|

Cryptography refers to the method of protecting critical informations, data and communications through the use of coding so that the person for whom the information is, can only read and process it. The prefix "crypt" means hidden and suffix "graphy" means writing.So from the name only, it is very clear the purpose for which it is actually implemented. 

It is associated with the process of converting plain text to a non- understandable text and vice versa. It stores the data in a particular form. It is not only used to secure data from theft but also used for user authentication purpose.

Earlier, Cryptography was typically synonymous to encoding but nowadays, it is mainly based on mathematical theory  and computer science practices.

In computer science, Cryptography refers to the communication techniques derived from mathematical concepts and rule based algorithms to transform messages to such a way that is hard to convert into normal language.

In the above video, it is very well explained that,

Modern cryptography concerns itself with four main objectives:

• Confidentiality: The information cannot be understood by anyone for whom it was unintended.
• Integrity:  The information cannot be altered in storage or transit between sender and intended receiver without the alteration being detected.
• Non-repudiation: The creator/sender of the information cannot deny at a later stage his or her intentions in the creation or transmission of the information.
• Authentication: The sender and receiver can confirm each other's identity and the origin/destination of the information.

Cryptography is used in many applications like, banking transaction cards, computer passwords, and e-commerce transactions

Types of cryptographic techniques that are used in general:

• Symmetric-key cryptography
• Hash functions
• Public-key cryptography

Hope this helped.
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