Fast inversion over large finite fields












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I was wondering if there is a "fastest" way to compute inversions over finite fields, especially if they are very large. I know that the standard way is the extended Euclidean algorithm, which runs in $O(log^2p)$, with $p$ being the characteristic of the finite field. In my case, $p=2^u3^vpm 1$ a very large prime. Is there a way to compute $a^{-1}text{ mod } p$ faster than with the Euclidean algorithm, in general, or maybe by somehow using the structure of the characteristic to our advantage?



Thank you for any help!










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  • 1




    $begingroup$
    I'm not an expert on this so I cannot say for sure, but... have you checked out the potential of using Montgomery representatives? One of the first hits to the buzzword Montgomery inverse.
    $endgroup$
    – Jyrki Lahtonen
    Jan 21 at 14:52
















0












$begingroup$


I was wondering if there is a "fastest" way to compute inversions over finite fields, especially if they are very large. I know that the standard way is the extended Euclidean algorithm, which runs in $O(log^2p)$, with $p$ being the characteristic of the finite field. In my case, $p=2^u3^vpm 1$ a very large prime. Is there a way to compute $a^{-1}text{ mod } p$ faster than with the Euclidean algorithm, in general, or maybe by somehow using the structure of the characteristic to our advantage?



Thank you for any help!










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    I'm not an expert on this so I cannot say for sure, but... have you checked out the potential of using Montgomery representatives? One of the first hits to the buzzword Montgomery inverse.
    $endgroup$
    – Jyrki Lahtonen
    Jan 21 at 14:52














0












0








0





$begingroup$


I was wondering if there is a "fastest" way to compute inversions over finite fields, especially if they are very large. I know that the standard way is the extended Euclidean algorithm, which runs in $O(log^2p)$, with $p$ being the characteristic of the finite field. In my case, $p=2^u3^vpm 1$ a very large prime. Is there a way to compute $a^{-1}text{ mod } p$ faster than with the Euclidean algorithm, in general, or maybe by somehow using the structure of the characteristic to our advantage?



Thank you for any help!










share|cite|improve this question









$endgroup$




I was wondering if there is a "fastest" way to compute inversions over finite fields, especially if they are very large. I know that the standard way is the extended Euclidean algorithm, which runs in $O(log^2p)$, with $p$ being the characteristic of the finite field. In my case, $p=2^u3^vpm 1$ a very large prime. Is there a way to compute $a^{-1}text{ mod } p$ faster than with the Euclidean algorithm, in general, or maybe by somehow using the structure of the characteristic to our advantage?



Thank you for any help!







finite-fields computational-complexity






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asked Jan 21 at 11:00









GemeisGemeis

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133








  • 1




    $begingroup$
    I'm not an expert on this so I cannot say for sure, but... have you checked out the potential of using Montgomery representatives? One of the first hits to the buzzword Montgomery inverse.
    $endgroup$
    – Jyrki Lahtonen
    Jan 21 at 14:52














  • 1




    $begingroup$
    I'm not an expert on this so I cannot say for sure, but... have you checked out the potential of using Montgomery representatives? One of the first hits to the buzzword Montgomery inverse.
    $endgroup$
    – Jyrki Lahtonen
    Jan 21 at 14:52








1




1




$begingroup$
I'm not an expert on this so I cannot say for sure, but... have you checked out the potential of using Montgomery representatives? One of the first hits to the buzzword Montgomery inverse.
$endgroup$
– Jyrki Lahtonen
Jan 21 at 14:52




$begingroup$
I'm not an expert on this so I cannot say for sure, but... have you checked out the potential of using Montgomery representatives? One of the first hits to the buzzword Montgomery inverse.
$endgroup$
– Jyrki Lahtonen
Jan 21 at 14:52










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