Secure Database of 450MB in android

I am creating an app having large database file of 450 MB I am storing it in SD card. and I want to secure it as It is having some sensitive data. If anyone can tell me the best way to secure that will solve my problem.

I also tried an sample but that was working for small DB file If I am using 450 MB Db, It is not working it taking a very big time.

And also please let me know whether it is possible or not to secure this much of large data.