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Data in the database is secured by using authentication, authorization and auditing mechanism, but the information stored in the datafiles can be read using any hex-editor tools or other OS level utilities, which is causing threat to sensitive  data. To overcome this limitation TDE is used to secure sensitive data, in database columns, stored in the datafiles. TDE is key-based access control mechanism. For each table, having encrypted column in it, an encryption key is generated which is again encrypted by database server’s master key. The database server’s master key is generated at the time when Wallet is ceated. The master key is stored outside oracle database in a Wallet and the keys for all tables containing encrypted columns are stored in dictionary tables in database. How to setup TDE: … Read entire article »

Oracle 11g introduces Case-sensitive passwords for database authentication. Along with this if you wish to change the password (temporarily) and reset it back to old , you will find that password field in dba_users is empty. Prior to 11g we could use following technique to change/restore password SQL> create user amit identified by amit; User created. SQL> grant create session to amit; Grant succeeded. SQL> conn sys as sysdba Enter password: Connected. SQL> select username,password from dba_users where username='AMIT'; USERNAME PASSWORD ------------------------------ ------------------------------ AMIT 9DEC0D889E8E9A6B SQL> alter user amit identified by abc; User altered. SQL> conn … Read entire article »