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
thanks
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
Asked: 2020-12-22 09:38:06 +0100
Seen: 673 times
Last updated: Dec 25 '20
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
            
Please add an example of a computation you want to do with Sage.
This is a follow-up from
i can't computing inverse GF(2^8) and Multiplication whith matrix 8 by 8
Also, don't hesitate to write in any language that feels more comfortable to you than English.
Inverse of what? Multiply what with what?