# Iterated Search Problems and Blockchain Security under Falsifiable Assumptions

@article{Garay2019IteratedSP, title={Iterated Search Problems and Blockchain Security under Falsifiable Assumptions}, author={Juan A. Garay and Aggelos Kiayias and Giorgos Panagiotakos}, journal={IACR Cryptol. ePrint Arch.}, year={2019}, volume={2019}, pages={315} }

We put forth a new class of search problems, iterated search problems (ISP), and study their relation to the design of secure blockchain protocols. We prove that (i) the Bitcoin blockchain protocol implies a hard ISP problem, but ISP hardness is not by itself su cient to prove its security, and (ii) a suitably enhanced class of ISPs is su cient to imply, via construction, a secure blockchain protocol in the common reference string (CRS) model. We then put forth a speci c proposal for an…

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