International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 05 | May -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 345 A SURVEY ON IMAGE STEGANOGRAPHY USING LSB SUBSTITUTION TECHNIQUE Beenish Siddiqui 1 , Sudhir Goswami 3 1 Student, Department of CSE, M.tech, Meerut Institute of Engg. & Technology, Uttar Pradesh, India. 2 Associate Professor, Department of CSE, Meerut Institute of Engg & Technology, Uttar Pradesh, India. ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract: Information security is one of the believable areas of research now-a-days. Steganography plays a shiny role in the information security. Its main aim is to covering sensitive information within a host such that the information existence remains confidential. By embedding secret message within other file steganography plays an important role of hiding messages for security purpose. The least significant bit (LSB) is one of the most important and simple method when one want to solve such problems. In this method, a number of bits of LSB is directly replaced by each pixel of the cover image with the embedded message. This paper describes the various techniques using the LSB substitution method to hide the data in images. Image steganography hides the data efficiently and effectively with the help of LSB substitution methods. Key Words—image steganography; cover image; stego image; Simple LSB substitution; Optimal LSB technique; 1.INTRODUCTION The fast development of the Internet deals great struggles to the transmission of secret data over networks. Secret data is candidate to unauthorized access. Therefore, to transmit the data secretly through internet becomes an essential topic. To keep the unauthorized user away, many different approaches have been proposed. To secure communication, Encryption and data hiding are two major methods in steganography. The method of changing the data (plaintext) into a cipher text via cipher algorithms and form the secret message, is called Encryption process. The secret message can be decrypted from the cipher text by the user that has keys, as shown in Figure 1. For any unauthorized user, this cipher text look like a meaningless and unreadable code until the user does not have a key. The data encryption still has some weaknesses although it is a respectable way to secure data. It makes the messages suspicious enough and streams of meaningless to attract unauthorized attention and give an impulse to recover them. Moreover, when the unauthorized users have trouble recovering the cipher text out of range, they might simply destroy them so that the authorized users cannot get the data in time. That is the reason why data hiding is a hot topic and has been under consideration of researcher recently [1] and [2] Figure-1: Simplified Model of Conventional Encryption. Hiding the secret data into multi-media data such as sounds, images or videos is called data hiding technique. Three different aspects contend with each other characterize the techniques as shown in Figure 2: capacity, robustness, and security. The amount of data bits that can be concealed in the cover medium relative to the size of the cover is called capacity . This is measured in bits per pixel (bpp), robustness is the capability of the stego medium to continue intact and resist the modification before an eavesdropper can modify or destroy the hidden data, and security concerned about the ability. Figure- 2: features of information-hiding system [3] steganography is the technique used to hide the existence data in different format such as text, images, audio, video etc.The Greek words steganos and graphia are the radix of the word Steganography and it meansdz hiding writingdz [Ͷ]. The main aim of steganography is to hide a message from a third party by secret communication. The cryptography differs from this in the manner that it does not hide the message like steganography, unlike it change the message and become the message unreadable to the third party or unauthorized users. Although steganography and cryptography are distinct and separate from each other, still there are some similarities between them, and some researchers define steganography as a type of cryptography since hidden communication is a type of secret writing [2]. Steganography uses audio, text, images, and video media for Encryption Decryptio n Plain text Plain text ke y ke y Cipher text