Set a password to encrypt files during archiving or to decrypt during extracting. The password is case-sensitive. If you omit the password in the command line, you will be prompted to enter it.
In the shell mode a password may be entered through Enter default password dialog or in the Archive name and parameters dialog.
Example
add the contents of the folder "games" to the archive " secret", using the password ZaBaToAd
WinRAR a -pZaBaToAd -r secret games*.*
Notes
if you wish to achieve real security do not use a password shorter than 8 characters or one which is easy to guess;
do not forget your passwords or your data will be completely lost