/**
	 * Encrypt a string as needed
	 *
	 * @param   string     $string      The string to encrypt
	 * @param   string     $key         The encryption key
	 *
	 * @return  string
	 * @since 3.2.0
	 **/
	public function encrypt(string $string, string $key): string;

	/**
	 * Decrypt a string as needed
	 *
	 * @param   string     $string      The string to decrypt
	 * @param   string     $key         The decryption key
	 *
	 * @return  string|null
	 * @since 3.2.0
	 **/
	public function decrypt(string $string, string $key): ?string;