Alexander Healy

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We introduce a new flavor of commitment schemes, which we call mercurial commitments. Informally, mercurial commitments are standard commitments that have been extended to allow for soft decommitment. Soft decommitments, on the one hand, are not binding but, on the other hand, cannot be in conflict with true decommitments. We then demonstrate that a(More)
We study the complexity of arithmetic in finite fields of characteristic two, F 2 n. We concentrate on the following two problems: First, we consider the explicit realization of the field F 2 n as F 2 [x]/(x 2·3 l +x 3 l +1) F 2 n , where n = 2·3 l. In this setting, we exhibit Dlogtime-uniform poly(n, t)-size T C 0 circuits computing exponentiation. To the(More)
Program checking, program self-correcting and program self-testing were pioneered by [Blum and Kannan] and [Blum, Luby and Rubinfeld] in the mid eighties as a new way to gain confidence in software, by considering program correctness on an input by input basis rather than full program verification. Work in the field of program checking focused on designing,(More)
We develop a general approach for improving the efficiency of a computationally bounded receiver interacting with a powerful and possibly malicious sender. The key idea we use is that of delegating some of the receiver's computation to the (potentially malicious) sender. This idea was recently introduced by Goldwasser et al. [14] in the area of program(More)
We construct a randomness-efficient averaging sampler that is computable by uniform constant-depth circuits with parity gates (i.e., in uniform AC 0 [⊕]). Our sampler matches the parameters achieved by random walks on constant-degree expander graphs, allowing us to apply a variety expander-based techniques within NC 1. For example, we obtain the following(More)
We introduce a new flavor of commitment schemes, which we call mercurial commitments. Informally, mercurial commitments are standard commitments that have been extended to allow for soft decom-mitment. Soft decommitments, on the one hand, are not binding but, on the other hand, cannot be in conflict with true decommitments. We then demonstrate that a(More)
We present an efficient mesh watermarking scheme whereby a vendor can embed purchaser-specific information (i.e. a user license) into a mesh upon the sale of the mesh. This watermark is robust to translation, rotation, uniform scaling, cropping and random perturbation of vertices (up to a threshold). Furthermore, since this method imposes only minor changes(More)
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