# faster GCD computation

how to obtained faster gcd computation over large prime field. if f1 and f2 are two polynomial over large prime field ex. p=256 it takes lot of time to perform gcd(f1,f2). how to speed up this computation.

May you be more precise? First, $p=256$ is not a prime, so you're note working over a large prime field, but on the contrary in a large extension of some small prime field... And what size of polynomials do you want to handle? A very quick test on polynomials of degree up to 250 (with a common factor of degree 100) is for instance fast enough to appear instant on my (standard) laptop.

p=256 thst is elliptic curve of 256 bits

You should simply give an example of the computation you are trying to perform! Because I am not able to make any sense of you latest comment.

As @B r u n o suggests, it would be a lot easier to answer the question if instead of

you provided an actual example that illustrates the problem and that other users can copy and paste into a Sage session to explore the problem in order to give help.

Something like:

Here the answer is computed in half a millisecond.