Locating modifications in signed data for partial data integrity
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We consider the problem of detecting and locating modifications in signed data to ensure partial data integrity. We assume that the data is divided into n blocks (not necessarily of the same size) and that a threshold d is given for the maximum amount of modified blocks that the scheme can support. We propose efficient algorithms for signature and verification steps which provide a reasonably compact signature size, for controlled sizes of d with respect to n. For instance, for fixed d the standard signature size gets multiplied by a factor of O(log n), while allowing the identification of up to d modified blocks. Our scheme is based on nonadaptive combinatorial group testing and cover-free families.
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