Database Security Oracle Question:

Shut the database
Backup the database
Modify/Include LOG_ARCHIVE_START_TRUE in init.ora file.
Start up the database.

To enable archiving
first shutdown the database in normal mode
then open ur parameter file and include a parameter
archive_log_dest=(give a OS level location)
then come out of it and at OS level create same directory which u have just mentioned in parameter file
then startup mount
then alter database archivelog
then alter database open
in order to know whether ur database is functioning in archive mode or not
type at sql promt
ARCHIVE LOGLIST;