Mental Card Gaming Protocols Supportive Of Gameplay Versatility, Robustness And Efficiency

Pennainan kad mental merupakan protokol kriptografi yang membolehkan pennainan yang ~ disahkan adil di kalangan parti-parti jauh yang penyangsi dan berpotensi menipu. Pennainan kad ini setidak-tidaknya patut menyokong-tanpa memperkenal~an parti ketiga yang dipercayai (TTP)--rahsia kad, pengesanan penipuan dan keselamatan bersyarat ke atas pakatan pemain. Tambahan kepada keperJuan asas ini, kami meninjau isu-isu pennainan kad mental yang berkaitan dengan fungsian permainan, keteguhan operasional dan kecekapan implementasi. Pengkajian kami diberangsang oleh potensi pennainan berasaskan komputer dan rangkaian yang melewati batas kemampuan kad fizikal, terutamanya pembongkaran maklumat terperinci kad (seperti warna, darjat, simbol atau kebangsawanan) sambil merahsiakan nilai keseluruhan kad tersebut. ~. Mental card games are cryptographic protocols which permit verifiably fair gameplay among a l< ~. priori distrustful and potentially untrustworthy remote parties and should minimally providewithout the introduction of a trusted third party (TTP)---for card confidentiality, fraud detection and conditional security against collusion. In addition to these basic requirements, we explore into gameplay functionality, operational robustness and implementation efficiency issues of mental card gaming. Our research is incited by the potential of computer-based and networkmediated gameplay beyond the capability of physical cards, particularly fine-grained information disclosure (such as colour, rank, symbol or courtliness) with preservation of card secrecy. On the other hand, being network connected renders the protocol susceptible to (accidental or intentional) disconnection attack, as well as other malicious behaviours

A novel SSGK to protect the communication process and shared data from unauthorized access

A cloud-based big data sharing system uses a storage facility from a cloud specialist co-op to impart data to authentic clients. As opposed to customary arrangements, cloud supplier stores the mutual data in the huge server farms outside the trust area of the data proprietor, which may trigger the issue of data classification. This paper proposes a secret sharing group key management convention (SSGK) to secure the correspondence procedure and shared data from unapproved get to. Not quite the same as the earlier works, a shared key is utilized to encode the common data and a secret sharing plan is utilized to circulate the shared key in SSGK. The broad security and execution investigations demonstrate that our convention profoundly limits the security and protection dangers of sharing data in distributed storage and spares about 12% of extra storage space

TSKY: a dependable middleware solution for data privacy using public storage clouds

Dissertação para obtenção do Grau de Mestre em Engenharia InformáticaThis dissertation aims to take advantage of the virtues offered by data storage cloud based systems on the Internet, proposing a solution that avoids security issues by combining different providers’ solutions in a vision of a cloud-of-clouds storage and computing. The solution, TSKY System (or Trusted Sky), is implemented as a middleware system, featuring a set of components designed to establish and to enhance conditions for security, privacy, reliability and availability of data, with these conditions being secured and verifiable by the end-user, independently of each provider. These components, implement cryptographic tools, including threshold and homomorphic cryptographic schemes, combined with encryption, replication, and dynamic indexing mecha-nisms. The solution allows data management and distribution functions over data kept in different storage clouds, not necessarily trusted, improving and ensuring resilience and security guarantees against Byzantine faults and at-tacks. The generic approach of the TSKY system model and its implemented services are evaluated in the context of a Trusted Email Repository System (TSKY-TMS System). The TSKY-TMS system is a prototype that uses the base TSKY middleware services to store mailboxes and email Messages in a cloud-of-clouds

Fair and Sound Secret Sharing from Homomorphic Time-Lock Puzzles

Achieving fairness and soundness in non-simultaneous rational secret sharing schemes has proved to be challenging. On the one hand, soundness can be ensured by providing side information related to the secret as a check, but on the other, this can be used by deviant players to compromise fairness. To overcome this, the idea of incorporating a time delay was suggested in the literature: in particular, time-delay encryption based on memory-bound functions has been put forth as a solution. In this paper, we propose a different approach to achieve such delay, namely using homomorphic time-lock puzzles (HTLPs), introduced at CRYPTO 2019, and construct a fair and sound rational secret sharing scheme in the non-simultaneous setting from HTLPs. HTLPs are used to embed sub-shares of the secret for a predetermined time. This allows to restore fairness of the secret reconstruction phase, despite players having access to information related to the secret which is required to ensure soundness of the scheme. Key to our construction is the fact that the time-lock puzzles are homomorphic so that players can compactly evaluate sub-shares. Without this efficiency improvement, players would have to independently solve each puzzle sent from the other players to obtain a share of the secret, which would be computationally inefficient. We argue that achieving both fairness and soundness in a non-simultaneous scheme using a time delay based on CPU-bound functions rather than memory-bound functions is more cost effective and realistic in relation to the implementation of the construction

Generalized threshold secret sharing and finite geometry

In the history of secret sharing schemes many constructions are based on geometric objects. In this paper we investigate generalizations of threshold schemes and related finite geometric structures. In particular, we analyse compartmented and hierarchical schemes, and deduce some more general results, especially bounds for special arcs and novel constructions for conjunctive 2-level and 3-level hierarchical schemes

Secret sharing schemes: Optimizing the information ratio

Secret sharing refers to methods used to distribute a secret value among a set of participants. This work deals with the optimization of two parameters regarding the efficiency of a secret sharing scheme: the information ratio and average information ratio. Only access structures (a special family of sets) on 5 and 6 participants will be considered. First, access structures with 5 participants will be studied, followed by the ones on 6 participants that are based on graphs. The main goal of the paper is to check existing lower bounds (and improve some of them) by using linear programs with the sage solver. Shannon information inequalities have been used to translate the polymatroid axioms into linear constraints