Biblio

Network coding (NC) can significantly increase network performance and make lossy networks more reliable. Since the middle nodes modify the packets during their path to destination, integrity of the original packets cannot be checked using classical methods (MACs, Signatures, etc). Though, pollution attacks are the most common threat to network coded systems, where an infected node can inject the data flow of a network with a number of false packets and ban the receiver from properly decoding the packets. A lot of work in the security of NC in resisting pollution attacks has been investigated in recent years, majority have the same security parameter 1/q. A Homomorphic MAC scheme is presented earlier to resist pollution attacks with a security level 1/qˆl, In this paper, we will show that the mentioned scheme is subject to known-plaintext attacks. This is due to that part of the key can be revealed in an initial process. Also, the whole key could be revealed if the key is used more than once. Then, a modification to the mentioned scheme is proposed to overcome this issue. Besides, the MAC length is adjustable according to the required security level and not variable according to the vector's length which will accordingly increase the performance and efficiency of the scheme.

Many-core microprocessor architectures are quickly becoming prevalent in data centers, due to their demonstrated processing power and network flexibility. However, this flexibility comes at a cost; co-mingled data from disparate users must be kept secure, which forces processor cycles to be wasted on cryptographic operations. This paper introduces a novel, secure, stream processing architecture which supports efficient homomorphic authentication of data and enforces secrecy of individuals' data. Additionally, this architecture is shown to secure time-series analysis of data from multiple users from both corruption and disclosure. Hardware synthesis shows that security-related circuitry incurs less than 10% overhead, and latency analysis shows an increase of 2 clocks per hop. However, despite the increase in latency, the proposed architecture shows an improvement over stream processing systems that use traditional security methods.

Cloud storage has been gaining in popularity as an on-line service for archiving, backup, and even primary storage of files. However, due to the data outsourcing, cloud storage also introduces new security challenges, which require a data audit and data repair service to ensure data availability and data integrity in the cloud. In this paper, we present the design and implementation of a network-coding-based Proof Of Retrievability scheme called ELAR, which achieves a lightweight data auditing and data repairing. In particular, we support direct repair mechanism in which the client can be free from the data repair process. Simultaneously, we also support the task of allowing a third party auditor (TPA), on behalf of the client, to verify the availability and integrity of the data stored in the cloud servers without the need of an asymmetric-key setting. The client is thus also free from the data audit process. TPA uses spot-checking which is a very efficient probabilistic method for checking a large amount of data. Extensive security and performance analysis show that the proposed scheme is highly efficient and provably secure.

In data outsourcing, a client stores a large amount of data on an untrusted server; subsequently, the client can request the server to compute a function on any subset of the data. This setting naturally leads to two security requirements: confidentiality of input data, and authenticity of computations. Existing approaches that satisfy both requirements simultaneously are built on fully homomorphic encryption, which involves expensive computation on the server and client and hence is impractical. In this paper, we propose two verifiable homomorphic encryption schemes that do not rely on fully homomorphic encryption. The first is a simple and efficient scheme for linear functions. The second scheme supports the class of multivariate quadratic functions, by combining the Paillier cryptosystem with a new homomorphic message authentication code (MAC) scheme. Through formal security analysis, we show that the schemes are semantically secure and unforgeable.