I need to convert elements of the finite field $GF(p^k)$, where $p$ is an odd prime, to octet strings.
To be more precise, I want to include elliptic curve points over $GF(p^2)$ in a Subject Public Key Info of an X.509 certificate. In the document IEEE P1363 there is a FE2OSP function which is probably not usable for that case.
Do you know of any well accepted standard which describes that encoding?