Browsing by Author "Wang, Zilong"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Adaptive Key Protection in Complex Cryptosystems with Attributes
    Wang, Zilong; Yao, Danfeng (Daphne); Feng, Rongquan (Department of Computer Science, Virginia Polytechnic Institute & State University, 2012)
    In the attribute-based encryption (ABE) model, attributes (as opposed to identities) are used to encrypt messages, and all the receivers with qualifying attributes can decrypt the ciphertext. However, compromised attribute keys may affect the communications of many users who share the same access control policies. We present the notion of forward-secure attribute-based encryption (fs-ABE) and give a concrete construction based on bilinear map and decisional bilinear Diffie-Hellman assumption. Forward security means that a compromised private key by an adversary at time t does not break the confidentiality of the communication that took place prior to t. We describe how to achieve both forward security and encryption with attributes, and formally prove our security against the adaptive chosen-ciphertext adversaries. Our scheme is non-trivial, and the key size only grows polynomially with logN (where N is the number of time periods). We further generalize our scheme to support the individualized key-updating schedule for each attribute, which provides a finer granularity for key management. Our insights on the required properties that an ABE scheme needs to possess in order to be forward-secure compatible are useful beyond the specific fs-ABE construction given. We raise an open question at the end of the paper on the escrow problem of the master key in ABE schemes.
  • Thumbnail Image
    Impact of Overweight Traffic on Pavement Life Using Weigh-In-Motion Data and Mechanistic-Empirical Pavement Analysis
    Wang, Hao; Zhao, Jingnan; Wang, Zilong (2015-06-04)
    The objective of this study is to evaluate the impact of overweight traffic on pavement life using mechanistic-empirical analysis approach. The state-of-practice mechanistic-empirical pavement design and analysis software (Pavement-ME) was used to predict pavement life under different traffic loading scenarios. Field performance data at the sites where the WIM data were collected were analyzed to estimate the pavement service life at field condition. The pavement structures considered in the analysis include flexible pavement and composite pavement with different combinations of layer thickness. Different distribution patterns were observed between the overweight and non-overweight traffic in terms of truck classes and axle load spectra. The reduction ratio of pavement life was used to normalize the effect of overweight truck at different conditions. A linear relationship was found between the overweight percentage and the reduction ratio of pavement life regardless of the variation in traffic loading and pavement structure. In general, it shows that 1% increase of overweight truck may cause 1.8% reduction of pavement life. Through the comparison between the pavement life predicted from the M-E analysis and estimated from field performance data, M-E analysis was proved to be a valid approach to quantify the impact of overweight truck on pavement damage in the network level.