Citation: Chen, P.; Lei, Y.; Niu, K.;
Yang, X. A Novel Separable Scheme
for Encryption and Reversible Data
Hiding. Electronics 2022, 11, 3505.
https://doi.org/10.3390/
electronics11213505
Academic Editor: Silvia Liberata Ullo
Received: 1 October 2022
Accepted: 26 October 2022
Published: 28 October 2022
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Article
A Novel Separable Scheme for Encryption and Reversible
Data Hiding
Pei Chen
1,2
, Yang Lei
1,2
, Ke Niu
1,2,
* and Xiaoyuan Yang
1,2
1
Key Laboratory of Network and Information Security Under the Chinese People Armed Police Force (PAP),
Xi’an 710086, China
2
College of Cryptography Engineering, Engineering University of PAP, Xi’an 710086, China
* Correspondence: niuke@163.com; Tel.: +86-029-138-0859-3399
Abstract:
With the increasing emphasis on security and privacy, video in the cloud sometimes needs
to be stored and processed in an encrypted format. To facilitate the indexing and tampering detection
of encrypted videos, data hiding is performed in encrypted videos. This paper proposes a novel
separable scheme for encryption and reversible data hiding. In terms of encryption method, intra-
prediction mode and motion vector difference are encrypted by XOR encryption, and quantized
discrete cosine transform block is permutated based on logistic chaotic mapping. In terms of the
reversible data hiding algorithm, difference expansion is applied in encrypted video for the first
time in this paper. The encryption method and the data hiding algorithm are separable, and the
embedded information can be accurately extracted in both encrypted video bitstream and decrypted
video bitstream. The experimental results show that the proposed encryption method can resist
sketch attack and has higher security than other schemes, keeping the bit rate unchanged. The
embedding algorithm used in the proposed scheme can provide higher capacity in the video with
lower quantization parameter and good visual quality of the labeled decrypted video, maintaining
low bit rate variation. The video encryption and the reversible data hiding are separable and the
scheme can be applied in more scenarios.
Keywords:
encrypted video; reversible data hiding; sketch attack; difference expansion; QDCT;
permutation; embedding capacity
1. Introduction
With the rapid development of the internet, a large number of videos are stored in the
cloud [
1
]. To protect the video content, these videos are stored in encrypted format [
2
]. To
achieve the goals of fast retrieval of encrypted video and protection of video after decryp-
tion, data hiding is combined with encryption to embed label information into encrypted
video [
3
]. Furthermore, in order to realize the lossless recovery of video, reversible data
hiding in encrypted videos emerges as the times require [4].
Recently, reversible data hiding in encrypted images has been widely studied [
5
–
7
].
However, due to the different structures of video coding, most schemes of reversible data
hiding in encrypted images are difficult to apply to video. Therefore, the research on
reversible data hiding in encrypted videos (RDH-EV) develops slowly and the framework
used is singular. In [
4
], the first RDH-EV scheme is presented. The intra-prediction mode
(IPM), the sign of motion vector difference (MVD), and the sign of quantized discrete cosine
transform (QDCT) coefficient are encrypted by RC4. Histogram shifting (HS) is imple-
mented to embed information in the encrypted QDCT coefficient. The scheme achieves the
separation of encryption and reversible data hiding, which means that decryption and data
extraction can be performed in any order. The most recent studies [
8
–
11
] apply the separa-
ble framework and focus on the improvement of data hiding. The scheme presented in [
8
]
focuses on the embedding capacity of data hiding and adds a scale factor for embedding
Electronics 2022, 11, 3505. https://doi.org/10.3390/electronics11213505 https://www.mdpi.com/journal/electronics
