Conditional Access System Research Articles

FORMATION OF A PERSONNEL DETECTION SYSTEM IN SMOKE-FILLED PREMISES BASED ON BIOMETRIC ACCESS SYSTEMS

In modern organisations, personnel are not at their workplace permanently and, accordingly, in case of emergency, they are at risk. There are a number of situations in which the access of even emergency services to the premises is very difficult to organise due to the regime of secrecy and the desire to preserve trade secrets. Additionally, the system of restricting the movement of workers in their places can be very limited on the part of management in order to maintain production discipline. The novelty of the study is determined by the fact that when using the detection system in case of fire or other emergency, its integration with the access verification and distribution system can be based on the use of integrated access systems. The authors show that the use of conditional access systems makes it possible to get employee lists at a faster pace and identify threats if certain technological complexes are used in their work. The practical significance of the study is determined primarily by the necessity for structural integration between conditional access systems and systems for recording and forecasting actions in emergency situations. It is proposed to use a model that allows to eliminate such differences.

A Computationally Efficient and Scalable Key Management Scheme for Access Control of Media Delivery in Digital Pay-TV Systems

In today’s Internet era, group communications in multimedia applications are becoming more and more popular. The issues of controlling illegal access to multimedia contents require efficient and secure mechanisms for distribution of common key called scrambling key or group key. In order to provide secure delivery of multimedia contents in digital pay-TV systems, a large number of keying information messages are exchanged for group key/scrambling key updates in the traditional key distribution schemes. In this paper we propose a Chinese Remainder Theorem (CRT) based key distribution protocol which is highly secure and computationally efficient. The proposed protocol, 1) has drastically reduced the computational complexity of Group Manager (GM) and members for updating the keys, 2) has greatly increased the security by using an additional secret parameter at Group Manager and members areas, 3) can efficiently handle large and dynamically updating groups and, 4) can update the group key in one message, without updating member’s key. With our proposed key distribution scheme, only legal members can access the multimedia contents correctly and the illegal access can be prevented. The proposed scheme is applicable in Conditional Access System (CAS) of digital pay-TV systems without increasing storage and communication overheads on GM and members. The comparative analysis of our proposed scheme with existing schemes in terms of computational cost assures the effectiveness of our scheme. As a proof of concept, we implement our scheme to a decentralized architecture-based key management system and demonstrate that the proposed scheme significantly reduces the computational complexity.

The transformation of broadcasting: public service broadcasting, the BBC and the distortion of new media markets

Broadcasting markets in Europe have traditionally been highly regulated, with large public subsidies seen as necessary to ensure that cultural and citizenship goals can be realised. While being outside of Polanyi’s purview when he wrote his seminal work The Great Transformation, these 'markets' exist alongside other public interest norms; in his words, they are embedded in society.1 In the last 20 years, broadcasting markets in Europe have undergone something of a 'transformation', in the sense that technological advances have facilitated a shift away from public provision towards a market-based model. The removal of spectrum constraints has led to new platforms and a proliferation of channels. More importantly, with the emergence of conditional access systems has come the growth of subscription and pay-per-view television, offering significant new revenue streams and the development of new markets in premium content. Latterly, non-linear television services have seen a shift in audience viewing behaviour, and the convergence between television and the internet heralds new, innovative modes of delivery of, and changing pricing mechanisms for, broadcasting services. So, as a consequence of technological developments, we see the rise of a new type of commodity in broadcasting services. Whereas once, such goods were universally available partly because their consumption was physically non-excludable, now technology facilitates charging and the emergence of a market based on willingness and ability to pay.

Efficient and Secure Key Management for Conditional Access Systems

In Digital TV service, subscribers get the access of channels of their interest. In conditional access systems (CAS), Control Word is used to deliver the multimedia content to legitimate subscribers securely. In order to update the Control Word frequently, a large number of messages are exchanged in the conventional key distribution systems. This article analyzes the strengths and weaknesses of the existing key distribution protocols for CAS and presents an efficient key distribution protocol for CAS based on Elliptic Curve Cryptography. The proposed protocol minimizes the storage cost and communication cost of subscribers. In addition to this, the proposed protocol facilitates the unrestricted channel package composition and minimum communication cost on rekeying. The proposed protocol also provides perfect forward and backward secrecy. As a result, the proposed protocol is well suited for Pay-TV systems.

A conditional access system with revocation for mobile pay-TV systems revisited

In pay-TV, conditional access systems (CAS) are used by a rights issuer to guarantee that only authorized subscribers gain access to TV channels. A CAS scheme that applies attribute-based access control through attribute-based encryption (ABE) with revocation was proposed by Yeh and Huang (2013) [1]. Yeh and Huang extend an existing ABE scheme with a revocation mechanism. We show that the CAS by Yeh and Huang has security and efficiency problems. Particularly, we show that the revocation mechanism proposed by Yeh and Huang is vulnerable to collusion attacks.

Efficient and secure conditional access system for pay-TV systems

In Digital TV service, subscribers get the access of channels of their interest. In Conditional Access Systems (CAS), multimedia content is delivered securely using the Control Word (CW). To frequent update of the CW, a large number of messages are exchanged in the conventional key distribution systems. In this paper, a centralized key distribution scheme based on dynamicity of the groups and with freedom of channel package composition is proposed. Scheme has also efficient mechanism of load balancing at Group Controller (GC) side. To speed up the search of the channel package in the existing database, Optimal Binary Search Tree (OBST) data structure and Finite State Machine (FSM) are used. Scheme also provides the efficient leaving and joining mechanism for single user as well as batch users.

Private Mobile Pay-TV From Priced Oblivious Transfer

In pay-TV, a service provider offers TV programs and channels to users. To ensure that only authorized users gain access, conditional access systems (CAS) have been proposed. In existing CAS, users disclose to the service provider the TV programs and channels they purchase. We propose a pay-per-view and a pay-per-channel CAS that protect users’ privacy. Our pay-per-view CAS employs priced oblivious transfer (POT) to allow a user to purchase TV programs without disclosing which programs were bought to the service provider. In our pay-per-channel CAS, POT is employed together with broadcast attribute-based encryption (BABE) to achieve low storage overhead, collusion resistance, efficient revocation and broadcast efficiency. We propose a new POT scheme and show its feasibility by implementing and testing our CAS on a representative mobile platform.

An effective key distribution for secure internet pay‐TV using access key hierarchies

AbstractDistribution of keys in a Conditional Access System takes long computation time because a huge number of keys is to be updated if any user leaves or joins the system. Moreover, it is necessary to send the keys securely to the authorized members. Thus, an effective key distribution protocol for Internet Pay‐TV system is designed in this article to lower the computation time taken to compute the re‐keying information. In the proposed protocol, when the Service Provider needs to refresh a new shared secret key and link values, only a few key updating operations are needed, and they can be achieved using four primary operations, namely, hash function, addition, subtraction, and multiplication. From the experimental results, we perceive that the proposed approach takes less computation cost, communication cost and storage cost compared with other competitive protocols available in the literature. Copyright © 2016 John Wiley & Sons, Ltd.

Interoperable conditional access with video selective encryption for portable devices

The pay-TV industry seeks to extend its reach to portable display devices. At the same time, it seeks to ensure a horizontal market by making interoperable the Conditional Access Systems (CASs) employed to protect content. To achieve interoperability for such devices, this paper proposes a form of selective encryption for video that allows simultaneous distribution of a small percentage of video data on a per-CAS basis, allowing sharing of the unencrypted video between the CASs. The bitrate overhead for each additional CAS enabled is found to be on average 7.41 %, whereas the computational overhead amounts to no more than 40 ms for the benchmark sequences tested. Adaptation of CAS to transparent encryption of scalable video is also demonstrated in this paper.

A reliable group key management scheme for broadcast encryption

A major challenge achieving scalable access control for a large number of subscribers in a public broadcast is to distribute key update messages reliably to all stateless receivers. However, in a public broadcast, the rekeying messages can be dropped or compromised during transmission over an insecure broadcast channel, or transmitted to receivers while they were off-line. In this study, we propose a novel group key management scheme. It features a mechanism to allow legitimate receivers to recover the current group key, even if they lose key update messages for long-term sessions. The scheme uses short hint messages and member computation. Performance analysis shows that the proposed scheme has the advantages of scalability and efficient rekeying compared to previous reliable group key distribution schemes. The proposed key management scheme targets a conditional access system in a media broadcast in which there is no feedback channel from receivers to the broadcasting station.

Public Service Broadcasting: Ownership, Funding and Provision

The British broadcasting system is heavily influenced by public service broadcasting (PSB) concepts and regulation. The debate over PSB has raged for decades and has to varying degrees been based on the proposition that there are myriad market failures in the provision of broadcast television programmes. The paper critically assesses these historically and in the light of developments in analogue and digital transmission of television and audio-visual programmes, the latter on different delivery platforms. The conclusions is that the claim that the structure, scale and scope of PSB can be explained or rationalised in terms of “textbook market failures” such as externalities and merit goods is deeply flawed and unconvincing especially in a digital age where subscription and conditional access systems are widely available. The chapter concludes with some observations on the funding of PSB, and particularly the current license fee, in the light of the UK Government review of the BBC’s Royal Charter in 2016.

Building a common encryption scrambler to protect paid broadcast services

Conditional access systems CAS are used in paid broadcasting services to ensure that only authorised users can access the protected content. It is therefore a crucial technology in developing paid broadcasting services. In a conventional paid broadcasting service environment, CAS technology based on a closed structure has many drawbacks. This paper proposes a common encryption-based scrambler to enable compatibility between different CAS technologies, thus ensuring equal access for all the business functions in the CAS.

An Identity-Based (IDB) Broadcast Encryption Scheme with Personalized Messages (BEPM).

A broadcast encryption scheme with personalized messages (BEPM) is a scheme in which a broadcaster transmits not only encrypted broadcast messages to a subset of recipients but also encrypted personalized messages to each user individually. Several broadcast encryption (BE) schemes allow a broadcaster encrypts a message for a subset S of recipients with public keys and any user in S can decrypt the message with his/her private key. However, these BE schemes can not provide an efficient way to transmit encrypted personalized messages to each user individually. In this paper, we propose a broadcast encryption scheme with a transmission of personalized messages. Besides, the scheme is based on multilinear maps ensure constant ciphertext size and private key size of each user and the scheme can achieve statically security. More realistically, the scheme can be applied to the Conditional Access System (CAS) of pay television (pay-TV) efficiently and safely.

Design and Evaluation of a New Scheme Based on Secret Sharing Mechanisms that Increases the Security of Conditional Access Systems in Satellite Pay-TV

This paper introduces a new scheme that confronts one of the critical flaws of conditional access (CA) systems employed in satellite pay-TV, the long or infinite cryptoperiod of a master key (MK). ...

Vulnerability of Control Word in Conditional Access Systems Environment

Vulnerability of Control Word in Conditional Access Systems Environment

A Simple and Efficient Re-Scrambling Scheme for DTV Programs

In order to guarantee pay-TV services, data of digital television (DTV) programs are scrambled by conditional access systems (CAS). In practical applications, some DTV transmitting nodes need descramble the scrambled DTV programs for editing purposes. After editing, how to re-scramble these edited programs is a challenging task since building CAS at transmitting nodes is expensive and insecure. In this paper, we proposed a novel scheme to solve this problem. Together with the recommended scheme, we also proposed techniques regarding video key data selection and extraction, synchronization of scrambled and descrambled transport stream (TS) packets, and scrambled/unscrambled interleaving multiplexer. The proposed scheme requires much lower complexity than existing methods while maintaining enough security for practical applications. Neither professional CAS equipment nor real-time common key (CK) transmitting is required by our re-scrambling scheme. Various experimental results demonstrated that the proposed re-scrambling scheme achieved superior performance in practical DTV systems, and it also obtained good compatibility with different CAS algorithms.

Huffman based conditional access system for key distribution in digital TV multicast

The advance of modern network technologies has made Digital TV systems available throughout the world. To provide secure media delivery in Digital TV systems, a large number of messages are exchanged for key updates in the conventional key distributed schemes of conditional access systems (CAS). In this paper, proposed a new multicast key distribution scheme based on Huffman grouping scheme of access control for conditional access system (CAS) in digital television multicast. The proposed key distribution scheme can greatly reduce the computation using fast Fourier transform and acquire higher efficiency and security using extended Euclidean algorithm. With this scheme, only authorized subscribers can watch the subscriber programs correctly. Unauthorized subscribers have no information to retrieve the correct programs over the networks. Moreover, the proposed scheme is more flexible in processing subscribers joining and leaving which is achieved by using Huffman based grouping scheme and is very important for service provider to dynamic manage the subscriber.

A novel key refreshment scheme increasing the security of conditional access systems in digital satellite pay-TV

This paper proposes a new scheme that faces one of the basic deficiencies of Conditional Access Systems (CASs) employed in satellite Pay-TV systems, Master Private Key's (MPK) infinite crypto period. The novelty of the proposed scheme is that it offers the ability to the administrator of the CAS to refresh users' MPKs at desired times. Thereby, the security of the CAS is significantly increased. The refreshment of the MPKs is accomplished through Lagrange Interpolation Method (LIM). In addition, the bandwidth consumption of several contemporary CASs of the Pay-TV market is presented. Based on those measurements, the bandwidth overhead that the new scheme imposes is proven to be negligible. The efficiency of the LIM for the refreshment of the MPK is verified through its implementation on a 65 nm Field Programmable Gate Array (FPGA). Finally, the required user's MPK refreshment time was achieved to be less than 0.15 ms.

The Principle of Conditional Access System and the Realization of Set-Top Boxes

Digital TV refers to a system which transforms the traditional analog signal into digital for processing, transmitting and receiving. In order to protect the interests of the operators and ensure the development of digital television, CAS (Conditional Access System) of digital TV uses various kinds of digital technology through the scrambling process of the program, so that only the authorized users can watch the scrambled programs. This paper mainly introduces the principle of CAS in current DTV, as well as elaborates the realization example of the CA running on the STi5105 chip platform and the detailed process from transplant to descrambling successfully.

A conditional access system with efficient key distribution and revocation for mobile pay-TV systems

Current mobile pay-TV systems have two types of Conditional Access Systems (CAS): group-key-based and public-key systems. The best feature of group-key-based systems is the ability to enjoy the broadcast nature in delivery multimedia contents, while the major advantage of public-key systems is consolidating the security foundation to withstand various attacks, such as collusion attacks. However, the problems of group-key-based systems include collusion attacks, lack of nonrepudiation, and troublesome key distribution. Even worse, the benefit of broadcast efficiency is confined to a group size of no more than 512 subscribers. For public-key systems, the poor delivery scalability is the major shortcoming because the unique private key feature is only suitable for one-to-one delivery. In this article, we introduce a scalable access control scheme to integrate the merits of broadcasting regardless of group size and sound security assurance, including fine-grained access control and collusion attack resistance. For subscriber revocation, a single message is broadcast to the other subscribers to get the updated key, thus significantly boosting subscriber revocation scalability. Due to mobile subscribers' dynamic movements, this article also analyzes the benefit of retransmission cases in our system. Through the performance evaluation and functionality comparison, the proposed scheme should be a decent candidate to enhance the security strength and transmission efficiency in a mobile pay-TV system.