network profile
| bio | website | |
|---|---|---|
| location | http://www.maths.manchester.ac.uk/~burdges/ | |
| age | 37 | |
| visits | member for | 1 year, 8 months |
| seen | Mar 27 at 11:49 | |
| stats | profile views | 5 |
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Dec 2 |
comment |
How do we find the last two correspondences in an otherwise known even permutation? In that case, my second linear time algorithm requires an $n$ bit array plus a few $O(log(n))$ bit counters and integers. |
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Dec 2 |
comment |
How do we find the last two correspondences in an otherwise known even permutation? If your going for n bits plus O(1), then : Iterate thorough the entries exhausting each elements cycle as far as possible to gradually build out the cycle(s) that end in $n-2$ and $n-1$. You use the n bit array to prevent reprocessing cycles. |
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Dec 2 |
comment |
How do we find the last two correspondences in an otherwise known even permutation? Inverse : Initialize $inverse[i] = -1$ for $i=1..n$. Set $inverse[P(i)] = i$ for $i=1..n$. If $inverse[n-2] = -1$ or $inverse[n-1] = -1$, then use parity to decide whether it's a fixed point or maps to $n-1$ or $n-2$, respectively. |
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Dec 2 |
answered | How do we find the last two correspondences in an otherwise known even permutation? |
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Nov 28 |
asked | Is there any serious discussion about using blinding intermediaries in digital currency scenarios? |
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Nov 26 |
comment |
How does the wider cryptographic community view non-abelian group based cryptography? There are cases where identifying a hidden subgroup has applications though. These results tell us that non-abelian finite simple groups cannot play the same role as prime numbers in cryptographic applications; hence my motivation for asking this question. |
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Nov 26 |
comment |
How does the wider cryptographic community view non-abelian group based cryptography? There is an industry of identifying finite groups both simple and non-simple using Monte Carlo methods, called black box group theory. Afaik, non-simple groups are treated using variations on the component analysis techniques from the CFSGs. |
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Nov 26 |
comment |
How does the wider cryptographic community view non-abelian group based cryptography? I'll verify further later but I believe the reference should be this article by Artin as well as its predecessor : onlinelibrary.wiley.com/doi/10.1002/cpa.3160080403/abstract |
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Nov 26 |
comment |
How does the wider cryptographic community view non-abelian group based cryptography? I'll track one down but it's the fact that all finite simple groups has distinct orders except for B_n(q) and C_n(q) with q odd and n>2, and A_3(2) and A_2(4), amusingly even wikipedia states it sans citation : en.wikipedia.org/wiki/List_of_finite_simple_groups |
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Nov 25 |
awarded | Teacher |
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Nov 25 |
awarded | Supporter |
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Nov 25 |
answered | What exactly is the impact of the hidden subgroup problem on cryptography? |
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Nov 25 |
comment |
How does the wider cryptographic community view non-abelian group based cryptography? Interesting thank! I'd naively assume any implementation would use only a bounded fragment of the infinite object for computational reasons, which avoids that side channel attack. You wouldn't be creating a finite group by imposing this bound, but maybe the CFSG still worms it's way into the picture somehow. |
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Nov 25 |
awarded | Student |
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Nov 25 |
asked | How does the wider cryptographic community view non-abelian group based cryptography? |
