Abstract:
Image, which covers the highest percentage of the multimedia data, its protection is very important. This can be achieved by cryptography. Image encryption plays an important role to ensure confidential transmission and storage of image over internet.It becomes an important issue that how to protect the confidentiality, integrity, and authenticity of image.A real–time image encryption faces a greater challenge due to large amount of data involved. This paper presents a review on image encryption techniques of both full encryption and partial encryption schemes in spatial, frequency & hybrid domains.

Keywords: Cryptography, Encryption, Decryption, Keys, Cipher text, Plain text, Symmetric key cryptography, Asymmetric key cryptography