However, the automatic crank described by the Banu Musa would not have allowed a full rotation, but only a small modification was required to convert it to a crankshaft.[34] Conical valve: A mechanism developed by the Banu Musa, of particular importance for future developments, was the conical valve, which was used in a variety of different applications.[31] Control valve: The Banu Musa brothers are credited with the first known use of conical valves as automatic controllers.[35] Cryptanalysis and frequency analysis: In cryptology, the first known recorded explanation of cryptanalysis was given by Al-Kindi (also known as "Alkindus" in Europe), in A Manuscript on Deciphering Cryptographic Messages.