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EMD/CRT: Difference between revisions
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==The [https://en.wikipedia.org/wiki/Chinese_remainder_theorem Chinese Remainder Theorem] is a useful result in the theory of prime numbers==
In June 2022 [[EMD]] used the CRT to devise a maximally collision-resistant checksum with an entropy in excess of 323 bits without the hassle of careful CRC design. He then wrote simple C programs to select near-optimal prime moduli based a candidate table cribbed from <[https://math.utm.edu/lists/2small/0bit.html https://math.utm.edu/lists/2small/]>, and to determine good 'geometries' (ie formats) for temporary files recording bitvectors totalling 547 30-bit words, suitable for recording whether or not a file having length congruent to each number in the range 1..2^14 exists in a given directory (aka 'folder'); 547x30 = 2^
* Traverse a filestore taking a snapshot of the directory structure, filenames, and file lengths.
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