说明：  代码使用Python标准库hashlib计算字符串的安全哈希值。 Python扩展库pycrypto也提供了MD2、MD4、MD5、HMAC、RIPEMD、SHA、SHA224、SHA256、SHA384、SHA512等多个安全哈希算法的实现。
(The code uses the Python standard library hashlib to calculate the safe hash value of the string. Python extension library pycrypto also provides MD2, MD4, MD5, HMAC, RIPEMD, SHA, SHA224, SHA256, SHA384, and other security hash algorithm implementation.)