We are currently working on a project to develop an "offline" mobile application that synchronises data with our current cloud software solution that would allow field workers in potential mobile black spots to still be able to carry out their work without a signal.
This would require (depending on the client size) up to 10GB of data to be downloaded to the device. Some of the data is of restricted classification (PII) and is just a defined read-only dataset specifically required for the role of the identity who downloaded them (not an entire db dump).
We defined a security policy that only one identity could be provided to the mobile phone app at any point in time (to protect the security of the data on the device). Although the burden would belong to the organisation on how they used it. This current policy defined proper rules such as device data encryption, and the correct AAA procedures.
With agreeable reason, customers have told us its not a valid to restrict the device to one user. As user A might work Monday, Tuesday but user B may work in the same role Wednesday, Thursday. Why should they fork the cost of multiple devices just to meet our policy.
My solution, is the downloadable device data must in entire belong to a defined set of roles which would be standard practice anyway. If the user must have those roles to be able to download the data, then a secondary identity must also have that role if the data has been downloaded (even if the user does not intend to use the offline capabilities).
Concerns then would be the integrity of the data. UserA could modify the device database to affect the work userB carried out (that may benefit userA). Having a separate encrypted database per user is not feasible (as its up to 10GB per user).
I can't seem to find any guidelines, or standards on this specific scenario of having a large subset of information on a device outside the central store. Is anyone aware of any material for this? NIST Special Publication 800-164 appears to be closest, but still doesn't really cover the problem
Any direction, or additional concerns would be helpful. I'm sure this is not a unique problem..