Hello, I am currently using the GF package to create finite fields: GF(2^16) = GF(2)[X]/(X^16+X^5+X^3+X^2+1) and GF(2^4) = GF(2)[X]/(X^4+X+1). But how can i get working into GF(2^16) defined over GF(2^4) ? That's with polynomials of degree at most 3, whose coefficients are in GF(2^4). Thanks, -- J