The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Video encryption has been heavily researched in the recent years. This survey summarizes the latest research results on video encryption with a special focus on applicability and on the most widely-deployed video format H.264 including its scalable extension SVC. The survey intends to give researchers and practitioners an analytic and critical overview of the state-of-the-art of video encryption narrowed down to its joint application with the H.264 standard suite and associated protocols (packaging/streaming) and processes (transcoding/watermarking).

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A Survey of H.264 AVC/SVC Encryption

A survey of video encryption algorithms

The need for fast and strong image cryptosystems motivates researchers to develop new techniques to apply traditional cryptographic primitives in order to exploit the intrinsic features of digital images. One of the most popular and mature technique is the use of complex dynamic phenomena, including chaotic orbits and quantum walks, to generate the required key stream. In this paper, under the assumption of plaintext attacks we investigate the security of a classic diffusion mechanism (and of its variants) used as the core cryptographic primitive in some image cryptosystems based on the aforementioned complex dynamic phenomena. We have theoretically found that regardless of the key schedule process, the data complexity for recovering each element of the equivalent secret key from these diffusion mechanisms is only ${O}$ (1). The proposed analysis is validated by means of numerical examples. Some additional cryptographic applications of this paper are also discussed.

On the Security of a Class of Diffusion Mechanisms for Image Encryption

In this paper, a novel algorithm for image encryption based on the hyper-chaotic system is proposed. In order to generate the initial conditions of the hyper-chaotic system, 256-bit long external secret key is used. The algorithm consists of three main sections. In the first section, instead of encrypting each pixel, the rows and columns of the image are encrypted using a row-column algorithm. In order to reach higher sensitivity, higher complexity and higher security, the second section employs masking process which is applied to each quarter of the image (i.e. sub-images) that is to be encrypted, using that sub-image data itself and one of the other sub-images and the average data of other quarters of image. Finally in the last diffusion section, the four most significant bit planes will be encrypted. Experimental results and performance analysis prove the viability of this cryptography based on privacy, integrity and authenticity. It is demonstrated that 2D Correlation Coefficients (CC), Mean Absolute Error (MAE), Encryption Quality (EQ), Mean Square Error (MSE), Peak Signal-to-Noise Ratio (PSNR), the Number of Pixel Change Rate (NPCR), the Unified Average Changing Intensity (UACI), entropy and decryption quality can satisfy security and performance requirements (CC? ?80, EQ?>?210.90, MSE?>?9555, PSNR? ?99.61243%, UACI?>?33.47573% and Entropy?>?7.99734). It can be seen that this algorithm yields better security performance in comparison to the results obtained from other algorithms.

A novel image encryption based on row-column, masking and main diffusion processes with hyper chaos

The popularity of multimedia applications is rapidly growing nowadays. The confidentiality of video communication is of primary concern for their commercial use, e.g. in video on demand services or in multiparty video conferences. Specific video encryption algorithms are strongly required in real-time multimedia communication to fulfill the strict timing requi-rements. In this paper we present a novel video encryption algorithm, called Puzzle, to encrypt video data in software. It is fast enough to meet real-time demands and provides a sufficient security. The algorithm can readily be incorporated into existing multimedia systems.

A novel encryption algorithm for high resolution video

SIP (Session Initiation Protocol) is becoming the mostly deployed signaling protocol for VoIP (Voice over IP). Security is of utmost importance for its usage due to the open architecture of the Internet. Recently, Yoon et al. proposed a SIP authentication scheme based on elliptic curve cryptography (ECC) that claimed to provide higher security than other schemes. However, as demonstrated in this paper, it is still vulnerable to off-line dictionary and partition attacks.

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Cryptanalysis of a SIP authentication scheme

Networked multimedia applications have matured in recent years to be deployed in a larger scale in the Internet. Confidentiality is one of the primary concerns of these services for their commercial usages, e.g. in video on de mand services or in video conferences. In particular, video encryption algorithms are strongly required that fulfill real-time requirements. In this paper we present the video encryption algorithm Puzzle to encrypting video streams in software. It is fast enough to fulfill real-time constraints and to provide a sufficient security. Puzzle is a video compression independent algorithm which can be easily incorporated into existing multimedia systems.

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Puzzle: a novel video encryption algorithm

Real-time video streams require an efficient encryption method to ensure their confidentiality. One of the major challenges in designing a video encryption algorithm is to encrypt the vast amount of video data in real-time to satisfy the stringent time requirements. Video encryption algorithms can be classified according to their association with video compression into joint compression and encryption algorithms and compression-independent encryption algorithms. The latter have a clear advantage over the former regarding the incorporation into existing multimedia systems due to their independence of the video compression. In this paper we present the compression-independent video encryption algorithm Puzzle, which was inspired by the children game jigsaw puzzle. It comprises two simple encryption operations with low computational complexity: puzzling and obscuring. The scheme thereby dramatically reduces the encryption overhead compared to conventional encryption algorithms, such as AES, especially for high resolution video. Further outstanding features of Puzzle are a good trade-off between security demands and encryption efficiency, no impairment on video compression efficiency, and an easy integration into existing multimedia systems. This makes Puzzle particularly well-suited for these security-sensitive multimedia applications, such as videoconferencing, where maximal security and minimal encryption overhead are desired simultaneously.

Fuwen Liu

Papers

A survey of video encryption algorithms

A novel encryption algorithm for high resolution video

Cryptanalysis of a SIP authentication scheme

Puzzle: a novel video encryption algorithm

Puzzle - an efficient, compression independent video encryption algorithm