Steganography is the practice of hiding information or data in a seemingly innocuous cover medium, such as message, file, image, audio, and video. In the past decades, many approaches of steganography in images were proposed for various applications. In social communication and the information highly exposed society, steganography requires high embedding capacity to transmit secret data efficiently. Generally, there is a trade-off between fidelity and embedding capacity. In this paper, we propose a novel and efficient data hiding algorithm in 24-bit color images with super high embedding capacity and acceptable peak signal-to-noise ratio (PSNR) using spatial-domain-adjacent mean. In the proposed algorithm, the embedding rate is about 7.4 bits per pixel (bpp) when the PSNR is nearly 30, and the embedding rate is about 8.88 bpp when the PSNR is nearly 25. The advantage of the proposed method is no need to transform data in another domain and without training data. Experiments also demonstrate the imperceptibility under some state-of-art steganalysis. The proposed steganography provides an efficient way to transmit sensitive information in the information highly exposed society.

Attribute-based encryption (ABE) is a useful tool for sharing an encrypted data to a target group. In a ciphertext-policy ABE (CP-ABE) scheme, a ciphertext includes a policy to indicate its receivers and only those receivers can correctly decrypt the ciphertext. Since this design leaks the receiver identity, it may raise a new security issue about user privacy. Some hidden-policy ABE schemes, where the policy is secretly protected, are proposed to keep user privacy. However, these hidden-policy ABE schemes rely on the user trying all possibilities to decide if it belongs to the wanted receiver group. The decryption costs too much and every potential receiver will run the decryption process in vain since it does not know the policy. In this work, we apply the deniability concept to solve this problem. The encryption scheme allows the sender to claim the ciphertext is for some receiver group while actually it is for another receiver group. Both receiver groups can correctly decrypt the ciphertext except that the real group can get the real message and the cover group will get the cover message. While coercion, the sender can definitely claim the ciphertext is for the cover group and the real group is kept confidential.

This work proposes a new and non-blind steganographic scheme for synthesized pitches. Synthesized music is popularly used to demonstrate early versions of compositions conveniently and at low-cost. They can also be utilized to pass secrets or obtain digital rights. The method consists of two procedures, of which the first is the realistic simulation of synthesized pitches using a computer and the second is the hiding of secrets during the generated simulated pitches. The first part of this paper reviews attempts to discover the fundamental patterns of synthesized pitches and to develop a strategy for generating approximate pitches using a computer. The component frequencies are used to generate a pitch in which to hide secrets. Legal receivers receive the referenced composition and frequencies, enabling them to generate the synthesized pitches according to the main frequencies of the referenced composition. Finally, the generated and received pitches are compared to identify the secret bits. As more frequencies are used to hide secret bits, more secret bits can be embedded in the synthesized pitches. The use of more frequencies makes synthesized pitches more realistic compared to real ones. The performance of the proposed method is also compared with that of competing methods and under common attacks.

Quantum computing is currently being researched in many countries, and if implemented in the near future, it may pose a threat to existing encryption standards. In the quantum computer environment, asymmetric encryption can be solved by Shor’s Algorithm in polynomial time, and the difficulty of breaking symmetric encryption using brute force is reduced from N times to square root N times by Grover’s Algorithm. We take the Advanced Encryption Standard as the theme and increase the key length from the original standard 192 bits and 256 bits to 384 bits and 512 bits, respectively, in order to maintain the security level of AES 192/256 under the environment of quantum computing, so we propose the key schedule of AES 384/512, and write the software in C++ on FPGA. The experimental results show that our scheme can achieve Level III and Level V security levels in a quantum computer attack environment. In addition to increasing the length of the key, we use the LUT method in the process of writing SubBytes to replace the array and speed up the computation to optimize the execution speed. In addition, the proposed scheme is still based on 128-bit computing blocks, rather than computing blocks in larger blocks.

An anonymous authentication and key agreement (AAKA) protocol provides anonymous members symmetric authentication and establishes a symmetric session key for secure communication in public networks. Today, numerous popular remote services are based on multi-server architecture, such as the internet of things (IoT), smart cities, cloud services, vehicular ad hoc networks (VANET), and telecare medicine information systems (TMIS). Many researchers have attempted to design AAKA protocols in multi-server environments for various applications. However, many of these have security defects, even if they have so-called “formal” security proofs. In this paper, we analyze related AAKA protocols to identify the common design defects, expound the process of designing secure AAKA protocols, and explain why the present AAKA protocols still suffer attacks, despite having security proofs. We instruct readers on how to design a secure AAKA protocol and how to prove the security. This paper will therefore be helpful for the design of new AAKA protocols, and for ensuring their security.

Online social network (OSN) users are increasingly interacting with each other via articles, comments, and responses. When access control mechanisms are weak or absent, OSNs are perceived by attackers as rich environments for influencing public opinions via fake news posts or influencing commercial transactions via practices such as phishing. This has led to a body of research looking at potential ways to predict OSN user behavior using social science concepts such as conformity and the bandwagon effect. In this paper, we address the question of how social recommendation systems affect the occurrence of malicious URLs on Facebook, based on the assumption that there are no differences among recommendation systems in terms of delivering either legitimate or harmful information to users. Next, we use temporal features to build a prediction framework with >75% accuracy to predict increases in certain user group behaviors. Our effort involves the demarcation of URL classes, from malicious URLs viewed as causing significant damage to annoying spam messages and advertisements. We offer this analysis to better understand OSN user sensors reactions to various categories of malicious URLs in order to mitigate their effects.