How to enable/disable case-sensitive password in oracle 11g

From oracle 11g password can be case sensitive by setting
SEC_CASE_SENSITIVE_LOGON = true in  initialization parameter file.

SQL> show parameter SEC_CASE_SENSITIVE_LOGON

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
sec_case_sensitive_logon             boolean     TRUE

Lets check the feature,
[oracle@configsrv1 ~]$ sqlplus /  as sysdba
SQL> create user soumya identified by das;

User created.

SQL> grant connect to soumya;

Grant succeeded.

[oracle@configsrv1 ~]$ sqlplus /  as sysdba
SQL> conn soumya/das
Connected.

Now we will check by providing the password in caps letter.
SQL> conn soumya/DAS
ERROR:
ORA-01017: invalid username/password; logon denied


Warning: You are no longer connected to ORACLE.

We can disable this feature by setting the parameter value to false.
SQL> alter system set SEC_CASE_SENSITIVE_LOGON= false scope=both;

System altered.

SQL> conn soumya/DAS
Connected.