International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 11 | Nov 2019 www.irjet.net p-ISSN: 2395-0072 © 2019, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 3522 A Survey on Cryptography, Encryption and Compression Techniques. Shiv Suraj Oberoi 1 , Yashika Varyani 1 , Dr. Deepak Chahal 2 1 MCA Student, Department of IT, Jagan Institute of Management Studies, Sector -05, Rohini, New Delhi. India 2 Professor , Department of IT, Jagan Institute of Management Studies, Sector -05, Rohini, New Delhi. India ------------------------------------------------------------***---------------------------------------------------------------------------------- Abstract: Data is any type of information that can be stored digitally. Security of data is an aspect that comes into play when the data which is digitally stored is to be protected. Data security is one of the major factors of this century, it refers to the protective measures taken to prevent unauthorized access to the data stored in personal computers, databases, and online websites or cloud services. Cryptography is a concept which helps the user to protect their data by giving them the necessary tools and algorithms for encryption and decryption of data. Cryptography is a very popular way of sending/receiving data in a very secretive way. Compression can be defined as reducing the number of bytes required to represent a set of data. Various techniques are used to reduce the size of data depending on the requirement of the user. Keywords: Data Encryption and decryption, Compression, Cryptography Concept, Security, Integrity. 1. Introduction Data can be defined as a collection of characters that is organized to serve a purpose. It can be anything ranging from text, number to images, videos. Raw data can be defined as data in its most basic form. Raw Data becomes “information” when it is processed and converted into a form which is convenient for movement and processing. In computing terms, Data can be described as a collection of 1’s and 0’s which are called “bits”. A bit is the smallest unit of data and a collection of eight bits is called a “Byte”. Database can be defined as an organized collection of data and Database Management System where created to organize and manipulate the information stored on it our main problem is the lack of standardization regarding procedures and techniques. Coming out of education and moving into the industry you can find yourself with knowledge of various methods and approaches, but no clear guide on best practices [1]. Cryptography is the practise of generating ciphers which are used to encrypt a message to ensure secure communication between the sender and the receiver. The encrypted message can only be decrypted by the person for whom the information was intended. Cryptography comprises of two very basic steps: Encryption and Decryption. Encryption is performed at the sender’s side and Decryption is done at the receiver’s side. Encryption is the process of converting information into non-human readable format using an algorithm. It is the process of applying cryptography. It is the process through which plaintext can be converted into ciphertext where the plaintext acts an input to the encryption process and the ciphertext acts as an output to the encryption process. Decryption is a converse process of encryption; it decrypts the encoded data into meaningful information. It is the process through which ciphertext is converted back to plaintext where the ciphertext acts an input to the decryption process and the plaintext acts as an output to the decryption process. Data compression is a technique through which the size of the data set is reduced by removing excessive information and modifying the bit structure of data in such a way that it acquires less space on the disk. Once data compression is done, file maybe fully recovered without any loss of actual information. Compressed data files can be easily uploaded and downloaded from the internet thus making the transfer of large sized files easier. Data compression techniques can broadly be divided into two categories: Lossy techniques and Loss-less techniques. In Lossy data compression, some part of the data is removed while compressing it but in Loss-less datacompression the same is achieved without the loss of data. In short, Data compression is the technique of encoding data to lesser number of bits than the original representation so that it requires less storage space and can be easily shared between networks. A compression tool is used to compress the data from and easy-to-use format to one optimized of compactness. Similarly, a decompression tool is used to restore compressed data to its original form. Data decompression is needed nearly in all cases of compressed data including, lossy and lossless compression. 2. Cryptography Cryptography is usually referred to as “the study of secret”. It is the transformation of understandable and readable information into a form which cannot be understood in-order to prevent data leakswith the helpof a key and an algorithm. Cipher is the algorithm which is