Selective image encryption in fractional wavelet domain

Fractional wavelet domain inherits the virtues of wavelet and fractional domain, to provide improved security. Non-consideration of data significance and emphasising on fractional order for the entire security consumes high computational resources without any proportional effect on the security. This article proposes an efficient selective encryption in fractional wavelet domain that encrypts only significant subbands using a chaotic stream cipher. Relationship between normalized information energy and perceptual information of a subband is utilized to select the significant subbands. Thorough performance and security analysis reflects better perceptual and cryptographic security with less computational time.