Function sodiumoxide::crypto::aead::chacha20poly1305::open

pub fn open(
    c: &[u8], 
    ad: Option<&[u8]>, 
    n: &Nonce, 
    k: &Key
) -> Result<Vec<u8>, ()>

open() verifies and decrypts a ciphertext c together with optional plaintext data ad using a secret key k and a nonce n. It returns a plaintext Ok(m). If the ciphertext fails verification, open() returns Err(()).