Avoiding data loss: suggested reading

Question

I am about to work on an app which handles extremely valuable data. Any loss of this data for the user would be very costly, so I'm interested in finding out more about the best architecture design for our needs.

The user will be inputting this data in their iPhone each day. The alternative to using this app is carrying around a piece of paper with this sensitive information on it. So while I know we can be more secure than a piece of paper, I want to make sure we also cover the user stories like "I flushed my phone down the toilet" or "my son deleted the app, where's my data?"

A service like Dropbox comes to mind, but I wouldn't want to require our users to have a Dropbox account; the syncing architecture must be transparent to the user. iCloud is out because web and Android versions may follow.

Can anyone suggest either some good reading on this subject, or some good frameworks to look at? I expect to use a node.js backend, and while we are targeting iPhone first, Android will follow.

The data itself consists of 2 tables, each with a small number of fields, with a many to many relationship. A few new rows will be created by the user each day, but the data will be small and highly compressible.

Answer 1

Turns out this is an extremely difficult issue. In data assurance (this isnt yet a security type situation although could become one because of the assurance aspect) there is ALWAYS a time element. As a simple example what happens if your use has locally updated some piece of data. Just before you have the ability to fully push the data to some cloud service, etc... he / she dumps it in the toilet. Even if good signal was there for transmitting the data there is time in transferring and time necessary for the cloud server to respond saying the data got there properly.

Generally in data assurance, you really have to work to the best you can. You will NEVER be able to solve all issues as there is no data center, nor link to a data center, etc... that is perfect. There is always a chance of data loss. Truly the best you can do, is SYNC as fast as data changes, and if there is loss of connection, as soon as the connection becomes alive again.

Now, for security. Security by itself does not create assurance. If the data itself is something that the customer does not want to lose, and that is his only requirement, then security is un-necessary. If he / she is also worried about other getting their hands on his data, then you have to be worried about data-in-transit (both up and down during syncing), and on the device itself. For the best potential security, encrypt the data locally on the device prior to pushing over the cloud. There are many known attacks that even if using SSL or other services, can get at the data. If you wish, locally encrypt a file, then you could for SOME added security still use SSL (at this point you will have doubly encrypted the data). You also want to sign the data so that there is little chance of it being manipulated in transit, or by the cloud server itself (if a hacker hacked the cloud server). Generally the way to protect the data while on device, you may choose to have the user input a password, and put some fairly strict rules around how passwords are formed, and how many tries you allow before you disallow attempts for 30 minutes or so.

You may also wish to store the data locally in an encrypted form. This way if someone gets the device, they still will need to have the password before they can get the data (unless of course they can crack the algorithm you use to generate the symetric key from the password).

In terms of online data service, you could use iCloud, etc... I am actually NOT a fan of anything cloud. I think it is SO counter enterprise / proprietary data, it isnt even funny. I think it actually almost laughable that so many of these phone / device manufacturers are going SOOOOO cloud based. I think they are abandoning the big companies, as NO big company I know of wants to place their proprietary data on a cloud server that THEY DONT CONTROL. In any case, I would argue that so long as you have a good local encryption scheme prior to sending out the data, then you should be OK. I would from an assurance perspective however look at where the servers are in locale. the reason being that if assurance of data is of prime concern, most larger IT setups like to have replicated data centers on opposing sides of the country / world etc... The reason for this is if an earthquake takes down the data center on one side of the country, it most likely will NOT take down the one on the other side of the country simultaneously. If the data centers for iCloud or whatever you can find are essentially in one locale, then you may consider syncing with one data center on the west coast, and choose a completely differing data center (in this case company) to sync with that is centered on the east coast.

This is all very high level, how you would implement this on an iPhone specifically we could also talk about, byt I hope this at least begins to help pave a path.