Health related data for a user is a privacy thing and its need to be very secure i.e. it needs to be stored in secure place. For example, while I was watching Apple's official video on Finger print unlock, they told that finger print data is stored at place where it is impossible to hack. So, for a curiosity, I have a question in mind that where these data are securely stored?
I have had a look at this link from Apple Documentation but could not found the information on it. One thing I have figured out is that data are encrypted and stored but where?
Does anyone has idea on the same?
Apple describes the security attributes of various iOS features in this document. To quote:
This data is stored in Data Protection class Protected Unless Open.
Access to the data is relinquished 10 minutes after device locks, and
data becomes accessible the next time user enters their passcode or
uses Touch ID or Face ID to unlock the device.
Read the "Encryption and Data Protection" section of the document to learn more about Data Protection. Any app can use the "Protected Unless Open" data protection class for its persistent data.
As you already know, NSUserDefaults is simple and effective for saving small, simple bits of data, like NSNumbers or NSStrings, to your device’s file system. But this data is in no way stored securely as hackers can access it pretty easily from the device.
You have figured out that sensitive data are encrypted. But you need to find the answer where it need to be stored. The Answer is:
Keychain Services:Apple has provided the Keychain Services API to deal with this problem and help developers build apps that safely handle passwords and other sensitive information.
Now the question might rase why?? and the answer is:
Keychain is great because data encryption automatically is taken care of before it is stored in the file system so there is no need to waste time building encryption algorithms.
You can go through this link for better explanation.
https://developer.apple.com/documentation/security/keychain_services
I need to read data from a measurement device and then save them in a file.
In this photo there is a list of commands (with check_sum that I don't know where to get) I can use for the communication:
Command List
Any help on how can I do that?
iOS 11 adds DeviceCheck, a mechanism to allow app developers to store a small amount of data (2 bits, along with a timestamp) that stays on the device, surviving deletion of the app. This is mean to identify for example, if a user has already participated in a free trial, or other similar purposes, while preventing a unique identification (fingerprinting) of the user. Documentation link
My question is couldn’t this theoretically be abused by developers to store much more data (potentially uniquely fingerprinting the user), by using a unique timestamp? Is there any mechanism keeping developers from doing this? If not this could be a significant privacy concern, defeating the point of this feature.
I could easily see malicious developers either storing the timestamp on their server to later uniquely identify the user, or simply waiting to store the data until a particular timestamp arrives, and encoding data in (the lower few bits of) the timestamp itself. Is this an actual risk?
According to the documentation it looks like the last_update_time timestamp that Apple gives you is in the YYYY-MM format. If you have more than a handful of users it's probably safe to assume that month-level granularity on the timestamp isn't enough to uniquely identify any user.
This is from Apple docs:
When you design a game that reports scores to Game Center, you should
also consider the security needs of your game. You want scores
reported to Game Center to be an accurate accounting of how players
are doing. Here are two suggestions:
Store your game’s preferences and saved games in a secure format,
rather than in clear text. If your game’s data is stored in clear
text, a player can download the saved game data using iTunes, modify
it, and resync it back to the device. This may allow the player to
achieve a higher score than you intended. Always set reasonable
minimum and maximum values for a leaderboard.
I know that data can be stored into .plist file or .xml or .json, even in a database. But all of that is non-encrypted plain text. What is considered as a secure format ? And what else methods/classes/techniques can be used to store sensitive data ?
If a hacker is determined enough and has the proper skill set, your stored data can be usually compromised regardless of storage method. It boils down to what your app's real-world applications are and the time and effort you are willing to put into keeping the data safe. Below are some options for you to consider:
NSUserDefaults
One of the most common and simplest ways to store data. Data is not encrypted.
Save string to the NSUserDefaults?
Plist Files
Also a common way to store data. Data is not encrypted.
Storing and Retrieving from a Plist
CoreData
Creates a model, manage relationship between different types of objects. By default, data is not encrypted.
http://www.appcoda.com/introduction-to-core-data/
http://www.raywenderlich.com/85578/first-core-data-app-using-swift
Keychain
Arguably the most secure way to store data on a non-jailbroken device. Data is encrypted.
https://stackoverflow.com/questions/16459879/how-to-store-a-string-in-keychain-ios
NSCoding
As Whirlwind pointed out, this is yet another storage method.
http://www.raywenderlich.com/1914/nscoding-tutorial-for-ios-how-to-save-your-app-data
http://nshipster.com/nscoding/
CommonCrypto Apple Framework
Low-level C coding. Data is encrypted.
https://developer.apple.com/library/ios/documentation/Security/Conceptual/cryptoservices/GeneralPurposeCrypto/GeneralPurposeCrypto.html
https://developer.apple.com/library/ios/samplecode/CryptoExercise/Listings/ReadMe_txt.html
Custom approaches
Store the data in the cloud thereby eliminate having it on the device altogether. Use the touch ID feature to authenticate the user and download the cloud data.
http://code.tutsplus.com/tutorials/ios-8-integrating-touch-id--cms-21949
https://developer.apple.com/library/ios/samplecode/KeychainTouchID/Introduction/Intro.html
The safest place to store your data is in the keychain, however it's still not 100% secure if users are on jailbroken devices. Follow Apple's guidelines on setting minimum and maximum values for a leaderboard.
Here's another SO post describing how you can store the information in an NSDictionary as NSData which is then encrypted and decrypted by your app.
thank you for taking the time and interest reading this and hopefully helping me out.
I need an unique user identifier for IOS, and what I mean with unique user identifier is a unique string that Apple provides that is unique for user not device, meaning that it will stay the same across devices. I thought about the Apple ID or something like that, but it´s not possible, because Apple does not provide it(at least not that I know of), but I want something similar to that.
It cannot be the UDID, because(besides being deprecated) it´s not persistent across devices. I want this in order to authenticate a user, without the user having to login, or signup. It is possible to do so, because some apps do so. I didn not log in or anything with another device, but it authenticated me. I had thought it was with the Apple ID, but that´s not possible to do.
I checked this answer: iOS unique user identifier. And it seems that it might be the solution, but I don't quite get it, as I don't see how it would be unique to every new user(being able to distinguish between multiple users, and the same user, but on different device).
I really appreciate people reading this and trying to help.
Thank you
PD: I use Titanium´s Appcelerator, not Apple´s IOS SDK or anything like that. But it´s not that important, I just want to get the process to be able to do it with Titanium's Appcelerator
PS: NOTE:
Thank you for answering and so fast!. I have read it many times and I just don't get it. Could you guys help me understand it a little bit better?
The way I understand it is this.
1.-Create an UUID(changes with every installation)
2.-Store it to the Keychain(As far as I know, the values saved on the keychain are local to the device) with a default service(I think Ill put it with the application's id-com.bla.bla-), and also a default account, I think Ill leave it as "users".
This will all be local, so every single installation will do this, with a different UUID for each installation(not necessary every user)
3.-Save the UUID to the NSUserDefaults.
4.-Save the UUID to the Cloud's public data store.(The UUID in the Cloud´s Data Store, Keychain and NSUserDefaults should be the same)
So, if 5 installations are run, the Cloud´s Public Data Store should be like this
An Array of 5 values:
[
XXXX-EEEEE-FFFFF,
SFSDFFWE-WERW-SDFS,
XXXX-XXXXX-XXXXX,
ZZZZZ-ZZZZ-ZZZZX,
XZXZZX-ZXZXZXS-ADADS
]
5.-All this will be executed every time you run the application, checking first if there is a value stored on the public cloud store. Here´s where I am confused, how will a different device know which UUID is yours? I mean, there are 5 different UUIDS to chose. Maybe it´s not supposed to be saved on the public data store, but on the private data store, but for that you would need to also identify each user. This is where I get so confused.
If there is no UUID set, execute the last 4 steps.
So, I get confused on the 5th step, most people understand that solution, without any more explanation, so I must be ignorant in the way something works, maybe the cloud services? I think the problem is that maybe I'm not understanding how the iCloud works, and how it stores it´s values. I just don't get how the 5th(random number, it might be the 2nd or 2000th) device of X running the app, will know that the UUID XXX... is the UUID of user X, and not the UUID of user Z.
Thank you again for answering so fast, I thought maybe I would have to wait a couple of days, not a couple of minutes. Forgive me for my ignorance, I'm kind of a noob on this matter, but I would like to learn. Been stuck on this problem for days
The answer you referred to is the correct way to identify your users. The solution is to save the value of that identification called a UUID (Unique User ID) - as opposed to a UDID (Unique Device ID).
The only down side to this of course for you as a developer is that the user could delete and install the app again and have a different ID.
As Daniel said, the UUID is the correct way to identify your users. I just want to add on this; you said that
I dont see how it would be unique to every new user
Well, accordint to this Wikipedia article:
Randomly generated UUIDs have 122 random bits...only after generating 1 billion UUIDs every second for the next 100 years, the probability of creating just one duplicate would be about 50%. The probability of one duplicate would be about 50% if every person on earth owns 600 million UUIDs.
So you can be pretty sure that the UUID will be unique to each user.
Additionally, the MAC address is based off of the MAC address of your ethernet card, the timestamp, and some other miscellaneous information. This adds to the uniqueness of the UUID as according to this question on Superuser:
[MAC addresses] are reasonably unique.
The first 3 octets define the manufacturer.
The last 3 octets are usually generated at the time of PROM burning. It's up to the manufacturer how they do this.
That obviously gives 16,777,215 possible unique MAC addresses per manufacturer. That's quite alot, so the manufacturer shouldn't re-use one.
So basically, the UUID adds an additional degree of uniqueness to the MAC address.
In summation, for your intents and purposes, the UUID would be perfect.
Hope this helps!