New name for rng
//! use orion::util;
//!
//! let mut salt = [0u8; 64];
-//! util::gen_rand_key(&mut salt).unwrap();
+//! util::secure_rand_bytes(&mut salt).unwrap();
//! let password = pbkdf2::Password::from_slice("Secret password".as_bytes());
//! let mut dk_out = [0u8; 64];
//!
