Hey since your file contains binary data it's extremly easy to encrypt it. Just assume a password and XOR every bit of your database with this password. Remember to covert your password into a binary number in your program or you will get an error. To decrypt the file use the same password.
Presently I am also working on encryption techniques and will give you the code as soon as possible.
You can also search the previous few months posts on encryption.

Good luck.

Kinjal