A scheme for threshold multi-secret sharing

Each year, film studios spend over $1 billion on the mechanics of duplicating and distributing films to exhibition venues located across the US With the advent of digital cinema projectors, much of this expense can be eliminated through more cost efficient digital distribution methods SATCOM links provide for a very efficient and cost effective digital cinema distribution model but piracy is a major concern; SATCOM links are easy to intercept and loss of a pristine, successful, first run film to pirates could have major financial repercussions The experience with Direct Satellite Services (DSS) has not been encouraging There are an estimated 3 million unauthorized users using cloned versions of the tamper resistant smart cards that seek to prevent this Furthermore, cinema stakeholders are risk adverse towards piracy based on the music industry's experience with Napsterization Music sales are down for the fourth year in a row (9% in 2002) and company valuations are down 40%, in part because of piracy As a consequence, there has been significant interest in providing location-based security for digital cinema distribution and forensic analysis in the event of piracy In this application, the same, large (25 to 190 Gbyte), encrypted media file might be used at multiple theatre locations nationwide but with distinct GeoLocked keys specific to the intended recipient location and its exhibition license This provides a secure and efficient point-to-multipoint distribution model for delivery via satellite or DVD At the exhibition hall, robust watermarking/steganographic techniques can introduce location, time and exhibition license information into the exhibition for subsequent use in piracy investigations This paper starts by describing a geo-encryption approach that builds on established cryptographic algorithms and protocols in a way that provides an additional layer of security beyond that provided by conventional cryptography It allows data to be encrypted for a specific location(s) or for specific area(s), eg a studio's campus area Constraints in time and velocity as well as location can also be enforced We then discuss a process of applying successive geo-encryptions at the originating node to enforce specific geographic routings for transmission to the final destination node We then describe the process of creating and distributing digital cinema content with an eye towards security requirements One of the more difficult issues is the large number of mutually mistrustful parties involved in the process We specifically show how time & location constraints introduced via geo-encryption can provide architectural features needed to allow untrusted parties to act cooperatively to bring the exhibition to the screen while maintaining a high degree of protection against piracy Suborning a single party does not lead to "loss of the film" We also show how these mechanisms can help protect the fiduciary interests of the various parties by giving each an enforceable say in whether or not the exhibition can proceed

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Location Based Encryption and Its Role In Digital Cinema Distribution

Traditional approaches to byzantine fault-tolerance have mostly avoided the problem of confidentiality. Current confidentiality-aware solutions rely on a heavy infrastructure investment or depend on complex key management schemes. The framework presented in this paper relies on a novel approach that combines byzantine fault-tolerance, secure storage and verifiable secret sharing to significantly reduce the additional infra-structure and complexity required by confidentiality protection. The proposed framework was compared to other solutions using a micro-benchmark, and an implementation of TPC-B and NFS.

Belisarius: BFT Storage with Confidentiality

The idea of secret sharing is to start with a secret, divide it into pieces called shares, which are then distributed amongst participants by the dealer. Only certain authorized subsets of participants can reconstruct the original secret. Applications for secret sharing schemes seem to be getting more important nowadays. For many circumstances, secret sharing has to provide more flexibility and functionality as per the need of an application. Secret Sharing has been an active research field for many years. Various secret sharing techniques have been developed to secure data, but there is a need to implement a secret sharing scheme with all augmented capabilities like general access structure, robustness against cheating shareholders, verifiability of the shares, proactive redistribution of shares etc. The intent of this paper is to explain the extended capabilities of secret sharing schemes and analyze the relation in application semantics and multifarious secret sharing schemes.

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An Explication of Multifarious Secret Sharing Schemes

The constant stream of privacy breaches, hacks, and outages in recent cloud-computing history has diminished the cloud's appeal. The future of cloud computing requires fundamental changes to account for data confidentiality. The authors discuss the ways in which data confidentiality in the cloud can be achieved.

Confidentiality in the Cloud

The concept of secret sharing can be used in a wide range of business application. A secret sharing system can implement the policies of secret sharing, and control the distribution of the secrets to the participants under the secret sharing policies. But, it can be damaged when the dealer cheating occurs. If the secret sharing system is implemented by Shamir's (t, n)-threshold scheme, one of the dealer's cheatings is that the dealer uses incorrectly polynomials to generate shadows (or shares) and distributes these error shadows to the participants. How can we detect this cheating? In this paper we propose a method to handle the detection of that the dealer uses wrong degree of the polynomial which the dealer chooses to hide the key. The main idea of the proposed method is that we ask the dealer to generate a certificate polymomial and one-bit verifying keys to provide information when participants do the detection process.

Detecting dealer cheating in secret sharing systems

The paper proposes a new key exchange scheme that is based on hyperspherical equation. Each participant fairly contributes a piece of final radius of a hypersphere. Thus, the proposed scheme can be modified to support the dynamic behavior of communication patterns of the peer-to-peer dynamic group.

A hypersphere oriented key exchange scheme for multiparty

In this paper a new Huffman tree decomposition technique is presented. The basis for this technique involves a set of encoding schemes. These encoding schemes exploit the technique of parallel computation to speed up the encoding and decoding procedures for the Huffman encoding scheme. The proposed encoding schemes also impose a complex structure on the resulting codewords such that the decoding procedures have the potential to become error correcting ones.

Chao-Wen Chan

Papers

Detecting dealer cheating in secret sharing systems

A hypersphere oriented key exchange scheme for multiparty

Huffman tree decomposition and its coding applications