  Reversible data hiding in encrypted images (RDH-EI) has attracted increasing
attention, since it can protect the privacy of original images while the
embedded data can be exactly extracted. Recently, some RDH-EI schemes with
multiple data hiders have been proposed using secret sharing technique.
However, these schemes protect the contents of the original images with
lightweight security level. In this paper, we propose a high-security RDH-EI
scheme with multiple data hiders. First, we introduce a cipher-feedback secret
sharing (CFSS) technique. It follows the cryptography standards by introducing
the cipher-feedback strategy of AES. Then, using the CFSS technique, we devise
a new (r,n)-threshold (r<=n) RDH-EI scheme with multiple data hiders called
CFSS-RDHEI. It can encrypt an original image into n encrypted images with
reduced size using an encryption key and sends each encrypted image to one data
hider. Each data hider can independently embed secret data into the encrypted
image to obtain the corresponding marked encrypted image. The original image
can be completely recovered from r marked encrypted images and the encryption
key. Performance evaluations show that our CFSS-RDHEI scheme has high embedding
rate and its generated encrypted images are much smaller, compared to existing
secret sharing-based RDH-EI schemes. Security analysis demonstrates that it can
achieve high security to defense some commonly used security attacks.
