The resistance of an iterated block cipher to most classical attacks can be quantified by some properties of its round function. The involved parameters (nonlinearity, degrees of the derivatives...) for a function F from GF(2^m) into GF(2^m) are related to the weight distribution of a binary linear code C_F of length (2^m − 1) and dimension 2m. In particular, the weight divisibility of C_F appears as an important criterion in the context of linear cryptanalysis and of higher-order differential attacks. When the round function F is a power permutation over GF(2^m), the associated code C_F is the dual of a primitive cyclic code with two zeroes. Therefore, McEliece's theorem provides a powerful tool for evaluating the resistance of some block ciphers to linear and higherorder differential attacks.