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In this paper, some means are proposed to improve the performances of the set-top box (STB) based media distribution schemes for IPTV. Firstly, the lightweight packet encryption is used to replace traditional complete encryption in order to reduce the time cost. Secondly, a method is introduced to form a unique customer code and generates a unique media copy for each customer in order to trace illegal redistributors. Thirdly, the desynchronization operations are introduced to make different copies in order to resist collusion attacks. Analyses and experiments show that the proposed packet encryption saves much time cost compared with traditional encryption and the saved time cost is enough for the added new operations. Additionally, the produced media copy is different from each other, and their collusion will generate a copy with much degradation, which can resist the content leakage from the gap between STB and TV set.

A scheme is proposed to implement commutative video encryption and watermarking during advanced video coding process. In H.264/AVC compression, the intra-prediction mode, motion vector difference and discrete cosine transform (DCT) coefficients' signs are encrypted, while DCT coefficients' amplitudes are watermarked adaptively. To avoid that the watermarking operation affects the decryption operation, a traditional watermarking algorithm is modified. The encryption and watermarking operations are commutative. Thus, the watermark can be extracted from the encrypted videos, and the encrypted videos can be re-watermarked. This scheme embeds the watermark without exposing video content's confidentiality, and provides a solution for signal processing in encrypted domain. Additionally, it increases the operation efficiency, since the encrypted video can be watermarked without decryption. These properties make the scheme a good choice for secure media transmission or distribution

Advanced video coding is recently announced and widely used, although the according protection means have not been developed thoroughly. In this paper, a secure AVC coding scheme is presented based on some partial encryption algorithms. During AVC encoding, such sensitive data as intra-prediction mode, residue data and motion vector are encrypted partially. Among them, the infra-prediction mode is encrypted based on exp-Golomb entropy coding, the intra-macroblocks' DCs are encrypted based on context-based adaptive variable length coding (CAVLC), and infra-macroblocks' ACs and the inter-macroblocks' MVDs are sign-encrypted with a stream cipher followed with variable-length coding. This encryption scheme is secure in perception, keeps format compliance, and obtains high time efficiency though reducing the encrypted data volumes. These properties make it practical to incorporate encryption/decryption process into compression/decompression process, and thus suitable for secure video transmission or sharing.

Some joint fingerprinting and decryption (JFD) schemes are recently reported. However, most of them need to be investigated before practical applications. In this paper, the audio JFD scheme proposed by Lemma et al. is investigated and evaluated. Some flaws are found in the scheme, such as the low encryption strength, the data overflow caused by encryption and the fragileness to collusion attacks. To improve the scheme, some means are proposed, such as the audio encryption without overflow and the collusion-resistant fingerprint encoding. Comparative experiments show that better performances are obtained by the improved means. The analysis method proposed in this paper can be used to investigate some other JFD schemes.

Recently, a collusion resilient video fingerprint method has been proposed utilizing desynchronization. But a question has not been considered for this method: secure transmission for multicast / broadcast. Because every copies using this method have different desynchronization, all the traditional fingerprint broadcasting techniques do not work. In this paper, we propose a method for securely broadcasting desynchronized video copies. The video is firstly lengthened and partially encrypted in the sender side and broadcasted to every user, and then on the receiver side, the video is desynchronized and embedded by fingerprint, and then decrypted. We give a method to implement this for MPEG-2 stream. Experiments indicate the effectiveness of the fingerprinted copies for collusion robustness and the efficiency of transportation. Security of the system is also analyzed with probable attacks and corresponding solution is proposed.

Collusion is a major menace to image fingerprint. Recently, an idea is introduced for collusion-resilient fingerprint by space desynchronizing including RST (rotation, scaling and translation) and random bending. In this paper, we proposed a new space desynchronized fingerprint method which is for large scale distribution: image is enlarged and encrypted at sender side; at user side, key sequence is used to only decrypt some parts of image and compose these parts to make a new image copy with fingerprint embedded. This method has two priorities: first, only one image is needed to send to or be downloaded by all users with fingerprint embedded; secondly, the embedded fingerprint is robust to collusion attack. For diminishing the degradation introduced by desynchronization, we consider the image content such as human face. Experiments indicate the effectiveness of our method.

A secure media distribution scheme is proposed in this paper, which distributes different copy of media content to different customer in a secure manner. At the sender side, media content is encrypted with a chaotic neural network based cipher under the control of a secret key. At the receiver side, the encrypted media content is decrypted with the same cipher under the control of both a secret key and the customer information. Thus, the decrypted media copy containing customer information is slightly different from the original one. The difference can be detected and used to trace media content's illegal distribution. The scheme's performances, including security, imperceptibility and robustness, are analyzed and tested. It is shown that the scheme is suitable for secure media distribution.

Multimedia data encryption is suitable for copyright protection. In this paper, a multimedia encryption scheme combined with block-based codecs (such as JPEG/JPEG2000, MPEG1/2, or H.261/263) is proposed, which permutes block positions, permutes coefficients (discrete cosign transform (DCT) coefficients or wavelet coefficients), and encrypts coefficient signs. It is extended to a perceptual encryption scheme and a secure video-on-demand (VOD) scheme. Theoretical analyses and experimental results show that this encryption scheme is of low-cost, supports direct bit-rate control, and is of higher robustness to transmission errors. These properties make it suitable for secure image or video transmission.

A secure distribution scheme is proposed for compressed videos, which is based on a compression domain watermarking algorithm. At the server end, the watermarking-based encryption algorithm is used to encrypt the compressed data stream. At the receiver end, the joint fingerprint embedding and decryption (JFD) algorithm is adopted to decrypt and fingerprint video data simultaneously. For the features of the watermarking algorithm, this scheme is easy to extract the fingerprint and detect the colluders, and is suitable for distributing compressed videos. Theoretical analysis and experimental results prove its practice.

Chaos and neural networks have both been used in data encryption because of their cipher-suitable properties, such as parameter-sensitivity, time-varying, random-similarity, etc. Based on chaotic neural networks, a hash function is constructed, which makes use of neural networks' diffusion property and chaos' confusion property. This function encodes the plaintext of arbitrary length into the hash value of fixed length (typically, 128-bit, 256-bit or 512-bit). Its security against statistical attack, birthday attack and meet-in-the-middle attack is analyzed in detail. Its properties make it a suitable choice for data authentication.

In this paper, a secure multimedia browsing scheme is proposed, which is constructed based on perceptual multimedia encryption and secure key distribution. In this scheme, multimedia data are encrypted perceptually under the control of user key and quality factor. This encryption process combining with Advanced Video Coding (AVC) is of low cost, and keeps file format unchanged. The key distribution scheme deals with user input, authenticates users, and controls the secure multimedia sharing process. Thus, only the users who have registered can obtain multimedia data. And they can be classified into several types according to their payment. The analyses and experimental results show that it is suitable for secure multimedia applications such as Video-on-Demand (VOD) system, Audio-on-Demand (AOD) system, pay-TV, videoconferencing systems, wireless or mobile multimedia, and so on.

A secure image transmission scheme based on JPEG2000 codec is proposed in this paper, which combines encryption with encoding and is suitable for real-time applications. In this scheme, the sensitive data are self-authenticated, then partial-encrypted during compression process, and the compressed data are encrypted by the lightweight encryption algorithm combined with error-correction codec. The self-authentication process can detect malicious tampering or transmission errors. The encryption process obtains suitable tradeoff between security and time-efficiency through encrypting data adaptively, and keeps the original system's error-robustness. The decryption process is symmetric to the encryption process. Experimental results show that this scheme obtains high perception security and time efficiency, and is thus suitable for secure image transmission over network.

With the wide application of multimedia data, multimedia content protection becomes urgent. Till now, various means have been reported, which can be classified into several types according to their functionalities, such as data encryption, digital watermarking or data authentication. They are used to protect multimedia data's confidentiality, ownership and integrity, respectively. For multimedia data authentication, some approaches have been proposed. In this paper, a wavelet-based multi-feature semi-fragile authentication scheme is proposed. According to the approximation component and the energy relationship between the subbands of the detail component, global feature and local feature are both generated. Then, the global watermark and local watermark are generated from global feature and local feature, respectively. The watermarks are then embedded into the multimedia data themselves in the wavelet domain. Both the feature extraction and embedding processes are controlled by secret keys to improve the security of the proposed scheme. In the receiver end, the extracted watermark and the one generated from the received image are compared to determine the tampered location. A new authentication method is designed and it is proved valid in the experiments. This authentication scheme is robust to general compression, sensitive to cutting, pasting or modification, efficient in real-time operation, and secure for practical applications.

Advanced Video Coding is recently announced and widely used, although the according protection means have not been developed thoroughly. In this paper, a selective encryption scheme is constructed on Advanced Video Coding. During AVC encoding, such sensitive data as intra-prediction mode, residue data, inter-prediction mode and motion vector are partially encrypted. This encryption scheme keeps secure against brute-force attack, replacement attack or known-plaintext attack, combines encryption process with compression process with low cost, and keeps the file format unchanged with some direct operations (such as displaying, time seeking, copying, cutting, etc.) supported. These properties make it suitable for secure video transmission.

A commutative watermarking and encryption scheme is proposed for media data protection. In the scheme, the partial encryption algorithm is adopted to encrypt the significant part of media data, while some other part is watermarked. The commutative property brings conveniences to practical applications in secure media transmission or distribution.