# Why GF(256) matrix only have zero and one number?

like this

```
sage: matrix(GF(2**8), [1, 2, 3, 4])
[1 0 1 0]
```

I just want do some matrix calculate mod 256, can any help me, please?

Why GF(256) matrix only have zero and one number?

like this

```
sage: matrix(GF(2**8), [1, 2, 3, 4])
[1 0 1 0]
```

I just want do some matrix calculate mod 256, can any help me, please?

add a comment

2

`K=GF(256)`

has characteristic 2, which result do you expect for `K(3)`

?

2

If you want to work mod 256, you should work with `Integers(256)`

, not `GF(256)`

. (The first of these is the ring `Z/256`

, the second is the field with 256 elements.)

```
sage: matrix(Integers(256), [1,2,3,4])
[1 2 3 4]
sage: matrix(Integers(256), [254, 255, 256, 257])
[254 255 0 1]
```

(edited to add the second example)

`IntegerModRing(256)`

is a synonym for `Integers(256)`

, by the way.

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Asked: ** 2019-08-04 13:27:35 +0200 **

Seen: **170 times**

Last updated: **Aug 06 '19**

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