Function encrypt 

pub fn encrypt(
    key: &SessionKey,
    nonce: &[u8; 24],
    aad: &[u8],
    plaintext: &[u8],
) -> Result<Vec<u8>, CryptoError>

Available on crate feature crypto only.

Encrypt plaintext using XChaCha20-Poly1305.

Arguments

• key - 32-byte session key
• nonce - 24-byte nonce (constructed from epoch, direction, counter)
• aad - Additional authenticated data
• plaintext - Data to encrypt

Returns

Ciphertext with appended 16-byte Poly1305 tag