symmetry key的用法和样例：
例句
- In symmetric cryptography systems, a single key that is used for both encryption and decryption.
在对称密码术系统中同时用于加密和解密的单个密钥。 - The public key cryptosystem or the asymmetric cryptosystem is an important way to implement and ensure information security.
公开钥密码系统或非对称密码系统是实现和保障信息安全的一种重要方式。
