Kalyanapu Srinivas*et al. /International Journal of Pharmacy & Technology IJPT| June-2017| Vol. 9 | Issue No.2 | 30174-30183 Page 30174 ISSN: 0975-766X CODEN: IJPTFI Available Online through Research Article www.ijptonline.com A CRYPTO KEY GENERATION FROM AN IMAGE WITH APPLICATION OF CRT Kalyanapu Srinivas*, Dr.V.Janaki, *Research Scholar, CSE Department, JNTU Hyderabad. Professor & HOD, CSE Department, Vaagdevi College of Engineering, Warangal. Email: kalyansr5555@gmail.com Received on: 22-05-2017 Accepted on: 28-06-2017 Abstract: For secured communication, several methods in cryptography have been proposed. These encryption mechanisms has greater importance as they are used for enhancing the security of information but there are many issues to be addressed in them and are abused by the unauthorized parties. Cryptography means encryption and decryption of information using keys generated by various algorithms. Such algorithms have a disadvantage of difficulty in remembering the keys which can also be easily traced, shared and stored. In this era, Cryptography with images has gained great attention due to importance of images in most of the multimedia applications. In this paper, we propose a novel Chinese Remainder theorem (CRT) based technique where images are used in generation of key. In our approach, from the selected point pixel values of a selected image the key for encryption and decryption is generated with CRT. Results shows that such keys from images with CRT are secure, stronger and also suitable keys of variable length can be obtained. Keywords: Encryption, Decryption, Information security, Images, CRT, key. 1. Introduction Data secrecy has become a great issue in multimedia data transmission applications as unauthorized access to data is increasing. To overcome such unauthorized accesses or modifications to information and to protect valuable information various types of cryptographic methods are introduced. Changing the original data to unreadable form using a key is the concept of cryptography. The key used here is generated involving typical process where the cryptanalyst cannot crack the key. Based on the utilization of the key there are two types of approaches existed in cryptography. a) Symmetric Cryptography- a common key between the sender and receiver for encryption and decryption. Examples include AES, IDEA, DES etc