Biblio

This paper proposes two adaptive Huffman coding hash tree algorithms to construct the hash tree of a file system. The algorithms are used to design the real-time proof of violation (PoV) scheme for the cloud storage service to achieve mutual non-repudiation between the user and the service provider. The PoV scheme can then generate cryptographic proofs once the service-level agreement (SLA) is violated. Based on adaptive Huffman coding, the proposed algorithms add hash tree nodes dynamically when a file is accessed for the first time. Every node keeps a count to reflect the frequency of occurrence of the associated file, and all nodes' counts and the tree structure are adjusted on-the-fly for every file access. This can significantly reduce the memory and computation overheads required by the PoV scheme. The file access patterns of the NCUCCWiki and the SNIA IOTTA datasets are used to evaluate the performance of the proposed algorithms. The algorithms are also compared with a related hash tree construction algorithm used in a PoV scheme, named ERA, to show their superiority in performance.

We propose an optical security method for object authentication using photon-counting encryption implemented with phase encoded QR codes. By combining the full phase double-random-phase encryption with photon-counting imaging method and applying an iterative Huffman coding technique, we are able to encrypt and compress an image containing primary information about the object. This data can then be stored inside of an optically phase encoded QR code for robust read out, decryption, and authentication. The optically encoded QR code is verified by examining the speckle signature of the optical masks using statistical analysis. Optical experimental results are presented to demonstrate the performance of the system. In addition, experiments with a commercial Smartphone to read the optically encoded QR code are presented. To the best of our knowledge, this is the first report on integrating photon-counting security with optically phase encoded QR codes.