exFAT¶
Version 2.7 of Disk Decipher adds support for the exFAT filesystem. Like the predecessor FAT32, Disk Decipher provides support for both reading and writing, so you are able to update your exFAT formatted encrypted containers.
Supporting exFAT is important since iOS 13 enables the usage of external USB disks which can contain very large containers (exceeding the FAT32 limits).
To enable exFAT filesystem support an in-app purchase is required.
Why an in-app purchase? I already paid for the app, why do I need to pay again for exFAT support?¶
exFAT is patent protected by Microsoft, details are provided on this page. This means an appropriate license is required to use exFAT.
To make the licensing process as easy as possible, Disk Decipher provides exFAT support as an in-app purchase. This in-app purchase is the lowest amount that covers both the exFAT licensing costs and the regular fee added by Apple.
The in-app purchase option allows me to keep track of the total number of purchases, so I can pay the required royalties.
To enable exFAT support simply try to mount an exFAT formatted encrypted container. Disk Decipher will automatically guide you through enabling exFAT support
Alternatively, you can also find the option to enable (and disable) exFAT support in the Settings page.
Five device limit¶
The in-app purchase will grant you the license to enable exFAT support on up to five devices. You can simply restore your purchase on a second, third, ... device (using the same Apple ID) to enable exFAT support.
To protect your privacy, Disk Decipher currently does not register the devices on which you enable exFAT support centrally to enforce the five device limit.
Do not enable exFAT support on more than five devices. Although this is technically possible, you will be violating the license agreement and liable for all resulting claims.
On purchasing exFAT support, you will be explicitly asked to agree to this license term.
But wait... iOS 13 supports exFAT formatted USB disks, is another licence really necessary?¶
iOS 13 includes built-in support to access exFAT formatted external drives. So, one could argue that the device is already exFAT licensed by Apple.
Does that also include usage of the exFAT filesystem within an app like Disk Decipher. At the moment, I don't know, as it depends on the exact license agreement between Apple and Microsoft.
If you can provide more information on this subject, please let me know. I would love to make exFAT support available free of charge. But I cannot risk a license violation claim.
Performance¶
Disk Decipher contains two implementations of the exFAT filesystem. If you bought exFAT support before January 2023, the app will use the original implementation, otherwise the current implemention. Due to a license restriction, it is not possible to switch between the two implementations.
You can easily determine which implementation the app is using by mounting an exFAT filesystem and tapping the (i) button in the bottom right corner. If the Filesystem section lists "FAT" as Module name, the original implementation is used.
The filesystem performance of the current implementation is better than the original implementation. If you bought exFAT support before January 2023 and performance is important for your use case, then please open a support ticket so we can discuss how to resolve this.