在 login.defs 中，BCRYPT 被列为一个选项，但是当我设置 ENCRYPT_METHOD BCRYPT 时，它不起作用。
#If set to MD5, MD5-based algorithm will be used for encrypting password
#If set to SHA256, SHA256-based algorithm will be used for encrypting password
#If set to SHA512, SHA512-based algorithm will be used for encrypting password
#If set to BCRYPT, BCRYPT-based algorithm will be used for encrypting password
#If set to YESCRYPT, YESCRYPT-based algorithm will be used for encrypting password
#If set to DES, DES-based algorithm will be used for encrypting password (default)
#MD5 and DES should not be used for new hashes, see crypt(5) for recommendations.
#Overrides the MD5_CRYPT_ENAB option
#
#Note: It is recommended to use a value consistent with the PAM modules configuration.
#
ENCRYPT_METHOD BCRYPT