Function open 

pub fn open<T, K>(blob: &[u8], key: Option<K>) -> Result<T, SerializationError>
where
    T: Decode<()>,
    K: AsRef<str>,

Decode a byte blob produced by seal back into T.

If key is None the default key is used. String literals and owned Strings are both accepted. Returns an error if the key is wrong, the blob is truncated, or the ciphertext has been tampered with — the Poly1305 tag prevents decryption of modified data.

Errors

• SerializationError::Cipher if authentication fails (wrong key or tampered blob).
• SerializationError::Decode if the decrypted bytes cannot be interpreted as T.