# how i can Computing inverse GF(2^8) and Multiplication

how i can Computing inverse GF(2^8) and Multiplication whith matrix 8 by 8 and sum whith matirx 8 by 1

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Please add an example of a computation you want to do with Sage.

( 2020-12-22 10:02:32 +0200 )edit

This is a follow-up from

( 2020-12-22 10:10:44 +0200 )edit

i can't computing inverse GF(2^8) and Multiplication whith matrix 8 by 8

( 2020-12-22 10:23:56 +0200 )edit

Also, don't hesitate to write in any language that feels more comfortable to you than English.

( 2020-12-23 00:57:55 +0200 )edit

Inverse of what? Multiply what with what?

( 2020-12-26 15:13:09 +0200 )edit

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Not completely sure what the question is.

To compute an inverse in GF(2^8) one can compute one over something.

Do these examples help?

sage: F.<a> = GF(2^8)
sage: b, c = a^8, a^15
sage: b, c
(a^4 + a^3 + a^2 + 1, a^5 + a^2 + a)
sage: d = c / b
sage: d
a^7
sage: aa = 1/a
sage: aa
a^7 + a^3 + a^2 + a

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