App contents encryption

[alexstuckey]

I'm making an app that requires its contents to be encrypted. I have seen other applications on the App Store that offer hardware encryption of data stored in the apps.

I need to encrypt multiple entire directories, and be able to access their contents on the fly if possible.

How would I go about doing this?

Thanks
Alex

[MattW]

Originally Posted by alexstuckey

I'm making an app that requires its contents to be encrypted. I have seen other applications on the App Store that offer hardware encryption of data stored in the apps.

I need to encrypt multiple entire directories, and be able to access their contents on the fly if possible.

How would I go about doing this?

Thanks
Alex

There's no hardware encryption (other than what Apple use at the hardware level to store files). You'll have to write your own encryption/decryption algorithm in software (there are plenty of options available to read about on the web). I'm sure there are open source solutions too if you don't want to write your own.

If the files you're going to encrypt are in your bundle, you'll have to write a Mac app to encrypt them before you compile your bundle. If they're user-generated files, you'll need to encrypt them in your app before writing them to the directory.

The only issue you're going to run into with the decryption might be speed, depending on how quickly and how often you need to access the data and what algorithm you use (although optimizing decryption algorithms is fun! ).

[clarket2]

Yes as MattW said there is no "hardware encryption" other than the security service on the device itself. You will need to implment the cryptography yourself. For symmetric block encryption e.g. AES you can use apple crypto library or something like https://github.com/dev5tec/FBEncryptor). For asymmetric encryption you will need certificates in different formats (DER, PKCS#12, etc) depending on what you want to do specifically and you can use the "Certificate, Key and Trust API" to encrypt, decrypt, sign and verify data etc.

My advice is to keep it simple as things like padding cause cause headaches. If symmectric encryption will suffice I would use it.

Thanks,

Tony