B4J Question Any way to encrypt images in Assets folder? (for security reasons)

If it can been seen on screen, it can be saved.

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Indeed any image on the screen can be stolen. Security always comes with a price. But security is like making it necessary to use a ladder: The "longer ladder" is used, the fewer people will reach it. We started with this question:

but is there a way I could prevent an easy modification of the images in the Assets (Files) folder?

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You can prevent adaptation by e.g. Calculate the MD5 hash and compare it with the MD5 of the original in the protected program code. Simple to apply for non-dynamic images to exit the pirated program or even more frustrating, starts an endless loop so that it looks like the program has stopped but is using cpu time.

I have things like company logos in there!

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The routines given by Meysampro is the first easy step. Now the marketing department probably won't have much of a problem with it as long as it brings extra brand awareness for free. However, with a sales department that starts to sell less because the program and the logo are changed, that clearly becomes a problem. Then it remains to use the "longer ladder" technique. Apply a backing that uses a random pattern and/or color in all directions with as little unused space as possible. This means that it is no longer just as easy to adjust, or adjustments become more or less visible.

MegatenFreak said:

change any images or assets or whatever they like

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This point is always possible, i.e. replace Bill Gates photo with Bill Clinton, as jar can be opened.
I am not stopping in encryption, but just stating the facts.
Complex encryption will take time, which is crucial for an app to operate, I think.

Well I think.. this point with assets can be a wish to Erel future updates for encrypting like zip with password... good point...

For now.. I think that you maybe need to mix sqlite dB with blob... also have watermarks...

Also blobs can be many parts... and some reversed... also have a small encrypted string with the enumeration order of blobs..

So one file db with all assets into it... but your way encrypted

So one file db with all assets into it... but your way encrypted

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Good idea, but the practice is unmanageable. Encrypting a database is also not without problems. After a lot of searching I found out that if you do that, you come into conflict with, for example, the unencrypted search of a B4X table search field.

MicroDrie said:

Good idea, but the practice is unmanageable. Encrypting a database is also not without problems. After a lot of searching I found out that if you do that, you come into conflict with, for example, the unencrypted search of a B4X table search field.

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Not encrypting... dB... only specific strings that will have the order of parts of blobs

Talking only for images... not text..

Thanks for all the points, guys.
You've given me a lot to work with. I'll put it all together and see what provides the best security with the least impact on performance.

why don't you just checksum them?
no need to encrypt, just check if the CRC is the one from the original image

Alessandro71 said:

why don't you just checksum them?
no need to encrypt, just check if the CRC is the one from the original image

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Great idea! I'd totally forgotten about checksum!

udg said:

If your sw needs Internet access anyway, you could store your images (and in general those files/resources you want to protect) on a remote server, then use SMM to download them at runtime.
Similar, but not adviced by Erel, would be to download your images the first time the app is run while storing them locally for any future reuse.

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Downloading Images via the internet to compose an interface would not be advisable. Erel is absolutely right.