oracle用户密码密码的生成

Oracle7-Oracle10,用DES加密密码，一直将用户名与密码一起做hash运算，例如sys/temp1与system/p1是相同的密码串。密码都强制转换成全大写。dba_users中的password可以看到密码密文。
SQL> grant dba to fwy6 identified by paic1234;
Grant succeeded
SQL> grant dba to fwy6p identified by aic1234;
Grant succeeded
SQL> select password from dba_users t where t.created>sysdate-1;
PASSWORD ------------------------------ DC3534D0BCEEDBE0 DC3534D0BCEEDBE0
SQL> alter user fwy6p identified by paic1234;
User altered
SQL> select password from dba_users t where t.created>sysdate-1;
PASSWORD ------------------------------ DC3534D0BCEEDBE0 C772C2461B9F9E8D

11g开始：仍然是将用户名与密码一起做hash运算，但允许大小写混合方式 alter user fwy2 identified by PAic1234;通过password|username的方式进行hash dba_users中的password不可以看到密码密文，而必须用sys用户查看user$视图
SQL> grant dba to fwy6 identified by paic1234;
Grant succeeded
SQL> grant dba to fwy6p identified by aic1234;
Grant succeeded SYS@epsstg> select password from user$ t where name in ('FWY6','FWY6P'); PASSWORD -------------------------------------------------------------------------------- DC3534D0BCEEDBE0 DC3534D0BCEEDBE0