A characterization of binary bent functions

A paper presented by Carlet (see IEEE Transactions on Information Theory, vol.41, p.1482-7, 1995) introduces a general class of binary bent functions whose elements are expressed by means of indicators of /sup n///sub 2/-dimensional vector-subspaces of (GF(2))/sup n/. An extended version of this class is introduced in the same paper where it is conjectured that this version is equal to the whole class of bent functions. We prove now that this conjecture is true.