A New PVSS Scheme with a Simple Encryption Function

A Publicly Verifiable Secret Sharing (PVSS) scheme allows anyone to verify the validity of the shares computed and distributed by a dealer. The idea of PVSS was introduced by Stadler in [18] where he presented a PVSS scheme based on Discrete Logarithm. Later, several PVSS schemes were proposed. In [2], Behnad and Eghlidos present an interesting PVSS scheme with explicit membership and disputation processes. In this paper, we present a new PVSS having the advantage of being simpler while offering the same features.Comment: In Proceedings SCSS 2012, arXiv:1307.8029. This PVSS scheme was proposed to be used to provide a distributed Timestamping schem

Entangled cloud storage

Entangled cloud storage (Aspnes et al., ESORICS 2004) enables a set of clients to “entangle” their files into a single clew to be stored by a (potentially malicious) cloud provider. The entanglement makes it impossible to modify or delete significant part of the clew without affecting all files encoded in the clew. A clew keeps the files in it private but still lets each client recover his own data by interacting with the cloud provider; no cooperation from other clients is needed. At the same time, the cloud provider is discouraged from altering or overwriting any significant part of the clew as this will imply that none of the clients can recover their files. We put forward the first simulation-based security definition for entangled cloud storage, in the framework of universal composability (Canetti, 2001). We then construct a protocol satisfying our security definition, relying on an entangled encoding scheme based on privacy-preserving polynomial interpolation; entangled encodings were originally proposed by Aspnes et al. as useful tools for the purpose of data entanglement. As a contribution of independent interest we revisit the security notions for entangled encodings, putting forward stronger definitions than previous work (that for instance did not consider collusion between clients and the cloud provider). Protocols for entangled cloud storage find application in the cloud setting, where clients store their files on a remote server and need to be ensured that the cloud provider will not modify or delete their data illegitimately. Current solutions, e.g., based on Provable Data Possession and Proof of Retrievability, require the server to be challenged regularly to provide evidence that the clients’ files are stored at a given time. Entangled cloud storage provides an alternative approach where any single client operates implicitly on behalf of all others, i.e., as long as one client's files are intact, the entire remote database continues to be safe and unblemishe

Semantically Secured Non-Deterministic Blum–Goldwasser Time-Based One-Time Password Cryptography for Cloud Data Storage Security

The security level of outsourced data is significant in cloud storage. Few research works have been designed for secured cloud data storage. However, the data security level was lower because the authentication performance was not effective. In order to overcome such drawbacks, a Semantically Secured Non-Deterministic Blum–Goldwasser Time-Based One-Time Password Cryptography (SSNBTOPC) Technique is proposed. The SSNBTOPC Technique comprises three steps, namely key generation, data encryption and data decryption for improving cloud data storage security with lower cost. Initially, in SSNBTOPC Technique, the client registers his/her detail to the cloud server. After registering, the cloud server generates the public key and secret key for each client. Then, clients in cloud encrypt their data with the public key and send the encrypted data to the cloud server for storing it in the database. Whenever the client needs to store or access the data on cloud storage, the client sends the request message to the cloud server. After getting the requests, cloud server authenticates the clients using their secret key and Time-based One-Time Password (TOTP). After the verification process, SSNBTOPC Technique allows only authorized clients to get data on cloud storage. During data accessing process, the client data is decrypted with their private key. This helps for SSNBTOPC Technique to improve the cloud storage security with a minimal amount of time. The SSNBTOPC Technique carried outs the experimental evaluation using factors such as authentication accuracy, computational cost and data security level with respect to a number of client and data. The experimental result shows that the SSNBTOPC Technique is able to increases the data security level and also reduces the computational cost of cloud storage when compared to state-of-the-art works