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8e399f9aa7
When I was originally designing my knockoff of Stein's algorithm, I simplified it for my own understanding by replacing the step that turns a into (a-b)/2 with a step that simply turned it into a-b, on the basis that the next step would do the division by 2 in any case. This made it easier to get my head round in the first place, and in the initial Python prototype of the algorithm, it looked more sensible to have two different kinds of simple step rather than one simple and one complicated. But actually, when it's rewritten under the constraints of time invariance, the standard way is better, because we had to do the computation for both kinds of step _anyway_, and this way we sometimes make both of them useful at once instead of only ever using one. So I've put it back to the more standard version of Stein, which is a big improvement, because now we can run in at most 2n iterations instead of 3n _and_ the code implementing each step is simpler. A quick timing test suggests that modular inversion is now faster by a factor of about 1.75. Also, since I went to the effort of thinking up and commenting a pair of worst-case inputs for the iteration count of Stein's algorithm, it seems like an omission not to have made sure they were in the test suite! Added extra tests that include 2^128-1 as a modulus and 2^127 as a value to invert. |
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| .. | ||
| colours.txt | ||
| cryptsuite.py | ||
| display.txt | ||
| eccref.py | ||
| lattrs.txt | ||
| scocols.txt | ||
| testcrypt.py | ||
| utf8.txt | ||
| vt100.txt | ||