These values are used to create two DES encryption keys.使用这些值创建两个数据加密标准密钥。Most DES students are sponsored by the National Department of Education.多数环境科学系的学生是由国家教育部资助的。DES defines some keys to be weak and therefore not suitable for encryption.数据加密标准定义了一些弱的、因而不适合用于加密的密钥。