Java – how secure is internal storage?

What I need:

For Android: I need to permanently save the data, but I can also edit (obviously read) it Users should not access this data – it can contain content with high scores and cannot be edited by users

My question

I will (and have) used internal storage, but I'm not sure how secure it is actually Here it says:

That's basically what I need – but is it really safe? Is it accessible from the root device (may only read?)? (or any other way?)

How about SQLite database or shared memory? Are they more suitable for saving (small amounts) of data?

Also: is it generally recommended to process "secret" data in different ways internally? (for example, it is not (internally) saved as an integer / string, but it is encrypted in some way)

Solution

It can read and write

This is the user's data, not your data It is the user's device, not your device Therefore, as long as the user's data is stored on their device, the user can edit the data

Now, if you want to prevent others from editing the data, encryption with a user supplied password is a reasonable measure This seems unnecessary for high game scores

Otherwise, if you do not want them to edit the data, do not store it on their device