Function tox_crypto::open

pub fn open(
    c: &[u8], 
    n: &Nonce, 
    pk: &PublicKey, 
    sk: &SecretKey
) -> Result<Vec<u8, Global>, ()>

open() verifies and decrypts a ciphertext c using the receiver's secret key sk, the senders public key pk, and a nonce n. It returns a plaintext Ok(m). If the ciphertext fails verification, open() returns Err(()).