Encrypted image-based reversible data hiding with public key cryptography from interpolation-error expansion

Abstract

This paper proposes an improved version of Shiu’s encrypted image-based reversible data hiding with public key cryptography (EIRDH-P). The original work vacates embedding room by difference expansion technique and embeds one bit into each pair of adjacent encrypted pixels. The data extraction and image recovery can be achieved by comparing all pairs of decrypted pixels. Shius’ work did not fully exploit the correlation inherent in the neighborhood of a pixel and required side information to record the location map. These two issues could reduce the amount of differences and in turn lessen the potential embedding capacity. This letter adopts a better scheme for vacating room before public key encryption using prediction-error expansion method, in which the pixel predictor is utilized by interpolation technique. The experimental results reveal that the proposed method offers better performance over Shiu’s work and existing EIRDH-P schemes. For example, when the peak signal-to-noise ratio of the decrypted Lena image method is 35, the payload of proposed method is 0.74 bpp, which is significantly higher than 0.5 bpp of Shius’s work.