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In this paper, we study the computational aspects of calculating the most widely used correlation coefficient: the Pearson product-moment correlation coefficient. We study various time-memory trade-off techniques which apply specifically to the cryptologic setting and present methods to extend already completed computations using incremental versions. Moreover, we show how this technique can be applied to second-order attacks, reducing the attack cost significantly when adding new traces to a dataset. We also present methods which allow one to split the potentially huge trace set into smaller, more manageable chunks in order to reduce the memory requirements. Our concurrent implementation of these techniques highlights the benefits of this approach as it allows efficient computations on power measurements consisting of hundreds of gigabytes on a single modern workstation.
We provide the first systematic exposition of the second generation of cryptocurrencies, including Bitcoin and the many alternatives that have been implemented as alternate protocols or ``altcoins.\'\' Drawing from a scattered body of knowledge, we put forward three key components of Bitcoin\'s design that can be decoupled, enabling a more insightful analysis of Bitcoin\'s properties and its proposed modifications and extensions. We contextualize the literature into five central properties capturing blockchain stability. We map the design space for numerous proposed modification, providing comparative analyses for alternative consensus mechanisms, currency allocation mechanisms, computational puzzles, and key management tools. We focus on anonymity issues in Bitcoin and provide an evaluation framework for analyzing a variety of proposals for enhancing unlinkability. Finally we provide new insights on a what we term disintermediation protocols, which absolve the need for trusted intermediaries in an interesting set of applications. We identify three general disintermediation strategies and provide a detailed comparative cost analysis.
I created a parser script that puts the raw cryptographic data of the PGP keys into a database. Doing this allows large scale searches for well-known vulnerabilities. DSA signatures with a duplicate $k$ value due to bad random numbers allow the calculation of the private key. Similarly analyzing RSA keys for shared prime factors allows factoring the modulus and thus also regenerating the private key.
A small number of breakable keys due to these weaknesses were found.