def valid_length
import bend-collections@1.0.0.0/src/crypto/aes/aes.bend as Aesimport Base
158# FIPS 197 Figure 4: a key of 16, 24 or 32 bytes; Nk = its length in words,
159# Nr = Nk + 6.
160def valid_length(+n: Nat) -> Bool:
161 Bool.or(Nat.is_eq(n, 16n), Bool.or(Nat.is_eq(n, 24n), Nat.is_eq(n, 32n)))