Definition ipd := Byte.repr 54.
Definition opd :=Byte.repr 92.
Definition IPAD:=bytesToBits (PAD.HM.sixtyfour ipd).
Definition OPAD:=bytesToBits (PAD.HM.sixtyfour opd).

Lemma IL: length IPAD = EQ.b.
unfold IPAD. rewrite bytesToBits_len, PAD.HM.length_SF, <- EQ.BS; trivial.