Function crypto_box_beforenm 

pub fn crypto_box_beforenm(
    public_key: &PublicKey,
    secret_key: &SecretKey,
) -> Result<Key, Error>

Computes a shared secret for the given public_key and private_key. Resulting shared secret can be used with the precalculation interface.

Compatible with libsodium’s crypto_box_beforenm.

Errors

Returns an error if public_key is an unacceptable low-order key.