# equation of mixcolumn in the aes field

$$c(y) = (03)y^3 + (01) y^2 + (01) y + (02)$$

Let $$d = (01)b$$ in the AES field $$GF(2^8)$$.

Provide exact equations for the bits $$d_i, 0 \leq i \leq 7$$, in terms of the bits $$b_i$$ of b.

Can some give me an example or hint? I don't know where to start..