val init : Native.ctx -> unitval init_keyed : Native.ctx -> Native.st -> int -> unitval init_derive_key : Native.ctx -> Native.st -> int -> int -> unitval update : Native.ctx -> Native.st -> int -> int -> unitval finalize : Native.ctx -> Native.st -> int -> unitval finalize_seek : Native.ctx -> int64 -> Native.st -> int -> int -> unit