Function encrypt 

pub fn encrypt(
    plaintext: &[u8],
    key: &Key,
    options: Option<EncryptOptions>,
) -> Result<EncryptionResult>

Encrypt data using AEAD encryption.

Prefers XChaCha20-Poly1305 if specified, otherwise uses AES-256-GCM.

Arguments

• plaintext - Data to encrypt
• key - 256-bit encryption key
• options - Optional encryption options

Returns

Encrypted data with algorithm, nonce, and authentication tag.