Function dryoc::classic::crypto_kdf::crypto_kdf_derive_from_key   
source · pub fn crypto_kdf_derive_from_key(
    subkey: &mut [u8],
    subkey_id: u64,
    context: &Context,
    main_key: &Key
) -> Result<(), Error>Expand description
Derives subkey from main_key, using context and subkey_id such that
subkey will always be the same for the given set of inputs, but main_key
cannot be derived from subkey.