CREATE OR REPLACE FUNCTION VERIFY_FUNCTION   (username varchar2,
  password varchar2,
  old_password varchar2)
  RETURN boolean IS
   n boolean;
   m integer;
   differ integer;
   isdigit boolean;
   ischar  boolean;
   ispunct boolean;
   digitarray varchar2(20);
   punctarray varchar2(25);
   chararray varchar2(52);

BEGIN
   digitarray:= '0123456789';
   chararray:= 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
   punctarray:='!"#$%&()``*+,-/:;<=>?_';

   -- Check if the password contains username
   IF NLS_LOWER(password) like '%'||NLS_LOWER(username)||'%' THEN
     raise_application_error(-20001, 'Password contains username');
   END IF;

   -- Check for the minimum length of the password
   IF length(password) < 10 THEN
      raise_application_error(-20002, 'Password length less than 10');
   END IF;

   -- Check if the password is too simple. A dictionary of words may be
   -- maintained and a check may be made so as not to allow the words
   -- that are too simple for the password.
   IF NLS_LOWER(password) IN ('welcome', 'database', 'account', 'user', 'password', 'oracle', 'computer', 'abcd') THEN
      raise_application_error(-20002, 'Password too simple');
   END IF;

   -- Check if the password contains at least one letter, one digit and one
   -- punctuation mark.
   -- 1. Check for the digit
   isdigit:=FALSE;
   m := length(password);
   FOR i IN 1..10 LOOP
      FOR j IN 1..m LOOP
         IF substr(password,j,1) = substr(digitarray,i,1) THEN
            isdigit:=TRUE;
             GOTO findchar;
         END IF;
      END LOOP;
   END LOOP;
   IF isdigit = FALSE THEN
      raise_application_error(-20003, 'Password should contain at least one digit, one character and one punctuation');
   END IF;
   -- 2. Check for the character
   <<findchar>>
   ischar:=FALSE;
   FOR i IN 1..length(chararray) LOOP
      FOR j IN 1..m LOOP
         IF substr(password,j,1) = substr(chararray,i,1) THEN
            ischar:=TRUE;
             GOTO findpunct;
         END IF;
      END LOOP;
   END LOOP;
   IF ischar = FALSE THEN
      raise_application_error(-20003, 'Password should contain at least one \
              digit, one character and one punctuation');
   END IF;
   -- 3. Check for the punctuation
   <<findpunct>>
   ispunct:=FALSE;
   FOR i IN 1..length(punctarray) LOOP
      FOR j IN 1..m LOOP
         IF substr(password,j,1) = substr(punctarray,i,1) THEN
            ispunct:=TRUE;
             GOTO endsearch;
         END IF;
      END LOOP;
   END LOOP;
   IF ispunct = FALSE THEN
      raise_application_error(-20003, 'Password should contain at least one \
              digit, one character and one punctuation');
   END IF;

   <<endsearch>>
   -- Check if the password differs from the previous password by at least
   -- 3 letters
   IF old_password = '' THEN
      raise_application_error(-20004, 'Old password is null');
   END IF;
   -- Everything is fine; return TRUE ;
   differ := length(old_password) - length(password);

   IF abs(differ) < 3 THEN
      IF length(password) < length(old_password) THEN
         m := length(password);
      ELSE
         m := length(old_password);
      END IF;
      differ := abs(differ);
      FOR i IN 1..m LOOP
          IF substr(password,i,1) != substr(old_password,i,1) THEN
             differ := differ + 1;
          END IF;
      END LOOP;
      IF differ < 3 THEN
          raise_application_error(-20004, 'Password should differ by at \
            least 3 characters');
      END IF;
   END IF;
   -- Everything is fine; return TRUE ;
   RETURN(TRUE);
END;
/

CREATE PROFILE PRIVILEGED_PROFILE LIMIT
    COMPOSITE_LIMIT UNLIMITED
    CONNECT_TIME UNLIMITED
    CPU_PER_CALL UNLIMITED
    CPU_PER_SESSION UNLIMITED
    FAILED_LOGIN_ATTEMPTS 5
    IDLE_TIME UNLIMITED
    LOGICAL_READS_PER_CALL UNLIMITED
    LOGICAL_READS_PER_SESSION UNLIMITED
    PASSWORD_GRACE_TIME 3
    PASSWORD_LIFE_TIME  90
    PASSWORD_LOCK_TIME 1
    PASSWORD_REUSE_MAX UNLIMITED
    PASSWORD_REUSE_TIME 365
    SESSIONS_PER_USER UNLIMITED
    PRIVATE_SGA UNLIMITED
    PASSWORD_VERIFY_FUNCTION VERIFY_FUNCTION
/

SQL> alter user test_user1 profile PRIVILEGED_PROFILE;

User altered.

SQL> alter user test_user1 identified by maa3#;

User altered.

SQL>

SQL> alter user TEST_USER1 password expire;

User altered.


C:\Users\user101>sqlplus test_user1/vik12#@testdb

SQL*Plus: Release 10.2.0.4.0 - Production on Tue Dec 24 16:41:29 2013

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.

ERROR:
ORA-28001: the password has expired


Changing password for test_user1 
New password: *****
Retype new password:
Password changed

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options

SQL> show user
USER is "TEST_USER1"