password_hash()PASSWORD_DEFAULT PHP 5.5

来自password_hash()函数：

PASSWORD_DEFAULT – Use the bcrypt algorithm (default as of PHP 5.5.0).
Note that this constant is designed to change over time as new and
stronger algorithms are added to PHP. For that reason, the length of
the result from using this identifier can change over time. Therefore,
it is recommended to store the result in a database column that can
expand beyond 60 characters (255 characters would be a good choice).

这是否意味着每当PASSWORD_DEFAULT更改时我将无法使用新的PHP版本,否则password_verify()将无法正确检查旧用户密码？

解决方法:

不,password_verify()将识别所使用的算法,因为它嵌入在您要验证的哈希中：这就是哈希的第一部分(例如$2y $)表示的