Image Compression for Authentication & Integrity of Data Based on Discrete Wavelet Transform

–The process of encryption and message authentication code is conventionally considered as orthogonal security mechanism. The objective of message security mechanism is to validate data authentication, whereas encryption is used to deform the message to achieve data confidentiality. The digital signature and watermarking methods are used for image authentication. Digital signature encodes the signature in a file separate from the original image. Cryptographic algorithms have suggested several advantages over the traditional encryption algorithms such as high security, speed, reasonable computational overheads and computational power. The frequency-domain techniques mainly used for watermarking of the human visual system are better captured by the spectral coefficients. The transforms are broadly categorized in two ways (a) Discrete Cosine Transformation (DCT) (b) Discrete Wavelet Transformation (DWT). It is very difficult to explain all the methods so in this paper we concentrated on DWT. The proposed research work is the integration of message authentication code as well as encryption where the parameterized hash value of an encrypted image is designed to be same as the hash value of the parent unencrypted original image. The hash value will be computed without decrypting the original data. Therefore the authenticity can be proven without revealing the actual information. A digital watermark and signature method for image authentication using cryptography analysis is proposed. The digital signature created for the original image and apply watermark. Images are resized before transmission in the network. After digital signature and water marking an image, apply the encryption and decryption process to an image for the authentication. The encryption is used to securely transmit data in open networks for the encryption of an image using public key and decrypt that image using private key. Keywords––Image Authentication, DWT, Integrity of Data.