I have created a suite of two different Flutter apps that share a single firestore database.
The first app generates a QR code that would then be scanned and verified by a user of the second app. The QR code information is a string that contains some information I don't want users to see by simply scanning the QR code with their camera app.
I want to encrypt the string in the first app before encoding it into a QR code, and decrypt the string in the second app after the QR code has been scanned, but that means I would need to have the encryption key accessible in both apps.
Would I have to hardcode this key into the apps or transmit the key through the database? How can I achieve this in the most secure way possible?
You can use almost any mechanism you want to transmit the keys, but the one thing you shouldn't do is transmit it through the same database as where you store the encrypted data - as that would put that data at risk if the database is compromised.
So mail them, text them, write them on a piece of paper and mail it, or you can organize an in-person meeting/party where you exchange them (h/t to Little Brother). It doesn't really matter how, as long as it's a different mechanism than you used to store/exchange the actual data that is encrypted with those keys.
You can hard-code them in the apps too, but what the keeps anyone from downloading that app too and using it? Or is that precisely what you want, in which case 👍
Related
I'm developing an app that's pretty simple, and the important part of it is the content, which consists of lots of info that has been gathered over many years. I want to format it in a nice way to show to the user.
When the user downloads the app and first loads it, it goes to the server to get the whole database into the phone. Then, he can see the important items, and sort/filter through them. To avoid somebody taking my database, I'll use a SSL connection. I know if they want they could use the app to see every piece of content one by one, but there's nothing to do about that.
The thing is: I have the data in the cloud (mine). I can securely download it using an SSL connection (any other ideas to secure the transfer?). When I get it here, I'll save it in a db (Core Data is the obvious choice).
How can I secure the data in the internal database, so if the app is hacked, someone cannot access the db? I would put it in the keychain but it's a rather large db for that and it's not that important. (It's not sensible info, just info I don't want anybody to get massively.)
The other thing I could do is to never store anything in the device and have the user always making calls to the cloud, but I think this would be too time consuming. And just give him the option to save their favorite picks to the device. But that's too time consuming and there is the sync issue.
This is a reference I looked up about a similar issue, without the part I'm asking answered:
How to encrypt iPhone upload and download of info?
Basically, the only choice is to use SqlCipher. Of course, you have to port it to iPhone yourself (unless someone else has posted a port since last I looked). But it's not an insurmountable task.
Of course, even with SqlCipher you have the challenge of storing the key somehow. There's no really secure way to do this -- you have to use some form of "security by obscurity".
Why not just have some private key info stored in the code, and then when you want to download the database just have it query the server with the key? That way you wan't need to worry about SSL or encryption in the downloading part. In regards to storing it I agree with Hot Licks, SqlCipher appears to be the best and only option. However watch out for encryption, as you will have to declare it to apple and get all kinds of export permits (http://stackoverflow.com/questions/2135081/does-my-application-contain-encryption).
Hope this helps,
Jonathan
I am developing app, which uses sqllite db. I want to provide security to DB. Is there any ways to provide security to SQLite DB so that no one can read it by hacking device or something else.
Should we provide any encrytion or apple provides their own security? Which are ways to provide app DB security?
Thanks
#Quentin's comment is right - as long as someone has physical acces to your device, it's only a matter of time until it's cracked. However, you can make that amount of time take so long that it's not worth it.
If you were to encrypt your database, the decryption key would also have to be stored on the device (assuming you want it to work offline). You could use the keychain to store this key - then they have to crack the iPhone's keychain before they can get access to your data.
The other alternative is to only let your app work while online - store the key on your server and have the user login and authenticate before you pass the key back to the app. This s a bit more work from you but will ensure that the key and the data are stored in different locations.
Finally (and most securely), you could store everything on your server - that way you control the data nd the key yourself and deice theft won't make the slightest bit of difference. however, if your data set is big this might make the ui of your app more complicated. And it won't work offline, obviously :)
I have some data I’ve spent months collecting, cleaning and structuring. The app I'm building will be able to search the data. So far I'm storing the sqlite file in the users filesystem and not on a remote server because I want the search result to be instant to give users the best experience possible, independently of their connection speed.
But I've just discovered anybody with a jailbroken phone can just "steal" the information store in my sqlite file.
The last thing I want is for someone to get the result of my hard work and publish it on a website which could potentially makes the app useless.
Is there any way to stop this from happening?
Thanks for your help!
What you want is a form of DRM. Ultimately, DRM cannot prevent a dedicated attacker from getting at the underlying data. Anything the user can access can, in theory, be accessed by a malicious application.
You can encrypt the rows of the database and hide the key somewhere in the app, but an intrepid hacker will find it. You can download the whole file on first run and encrypt it with a key unique to that device, but then you have to store the key somewhere or have an algorithm for regenerating it--and a hacker can get at either (even if it's in the keychain.) If you require a network connection and use a key generated from something server-side and client-side... well, an attacker can just spoof the request and get that server-side component anyway.
So it really depends how secure you want to be. If you just want to keep honest people honest, simple encryption is often good enough. If you want to make a bulletproof DRM system... you'd be the first to accomplish it.
You can use Encrypted Core Data to secure your data.
This library actually decrypts your database at runtime. You can leave your PASSCODE in your .m file. (My assumption is that it is difficult to get the hardcoded PASSCODE from the object file)
And as #jonathan put it, if some person is desperate to get your data, they will.
EDIT:
As Zaph mentioned in the comments section, do not try to put password in your code either directly, or by obfuscating them in your code by some logic, as any one who is desperate to get your key could reverse engineer your binary and get it.
Is it possible to reverse-engineer my iPhone application?
I'm storing some healthcare data on a mobile phone and I'd like to know what the best system of encryption is, to keep the data secure. It's basically a bunch of model objects, that I'm serializing and storing using NSKeyedArchiver / the equivalent on Blackberry (the name eludes me for now)
Any tips? I don't want to make up security protocols as I go along, but one of the other threads suggested the following approach.
Generate a public / private key pair
Store the public key
Encrypt the private key with a hash of the user's password.
Use the public key to encrypt the byte stream.
Decrypt the pvt key, keep it in memory, whenever the user logs in, and decrypt the stored data as needed.
Is there a more standard way of doing this?
Thanks,
Teja.
Edit: I appreciate it that you're trying to help me, but the things currently being discussed are business level discussions, on which I have no control of. So rephrasing my question, if you ignore that it's healthcare data, but some confidential data, say a password, how would you go about doing it?
There might be an easier way for secure data storage. With iOS 4.0 apple introduced system provided encryption of application documents. This means that the OS is responsible for doing all the encryption and decyryption in a fairly transparent way.
Applications that work with sensitive user data can now take advantage of the built-in encryption available on some devices to protect that data. When your application designates a particular file as protected, the system stores that file on-disk in an encrypted format. While the device is locked, the contents of the file are inaccessible to both your application and to any potential intruders. However, when the device is unlocked by the user, a decryption key is created to allow your application to access the file.
So only when your app is active, the files can be read back in unencrypted format. But the nice thing is that they are always encrypted on disk. So even if someone jailbreaks the device, or backs it up, the retrieved files are worthless.
This was probably introduced to conform to some specific data security standard that is required. I can't find that anywhere though.
For more info see the iOS 4.0 release notes.
http://en.wikipedia.org/wiki/HIPAA
Make sure you read and understand this!
edit: Sorry, didn't even bother to check to see where the OP is from, but even if they aren't from the USA there are still some good practices to follow in HIPAA.
HIPPA is a business practice and total system level privacy/security regulation. As such, an app can't comply by itself on random hardware for a random user. You need to determine how your app fits into a client health care provider's total regulatory compliance process before you can determine what algorithm might be found to comply with that process.
My best advice would be, don't store sensitive data in the user's mobile phone.
If that is not an option for you, then some kind of public/private key encryption, such as one you described, would be the next best option.
Let's say I need to access a web service from an iPhone app. This web service requires clients to digitally sign HTTP requests in order to prove that the app "knows" a shared secret; a client key. The request signature is stored in a HTTP header and the request is simply sent over HTTP (not HTTPS).
This key must stay secret at all times yet needs to be used by the iPhone app.
So, how would you securely store this key given that you've always been told to never store anything sensitive on the client side?
The average user (99% of users) will happily just use the application. There will be somebody (an enemy?) who wants that secret client key so as to do the service or client key owner harm by way of impersonation. Such a person might jailbreak their phone, get access to the binary, run 'strings' or a hex editor and poke around. Thus, just storing the key in the source code is a terrible idea.
Another idea is storing the key in code not a string literal but in a NSMutableArray that's created from byte literals.
One can use the Keychain but since an iPhone app never has to supply a password to store things in the Keychain, I'm wary that someone with access to the app's sandbox can and will be able to simply look at or trivially decode items therein.
EDIT - so I read this about the Keychain: "In iPhone OS, an application always has access to its own keychain items and does not have access to any other application’s items. The system generates its own password for the keychain, and stores the key on the device in such a way that it is not accessible to any application."
So perhaps this is the best place to store the key.... If so, how do I ship with the key pre-entered into the app's keychain? Is that possible? Else, how could you add the key on first launch without the key being in the source code? Hmm..
EDIT - Filed bug report # 6584858 at http://bugreport.apple.com
Thanks.
The goal is, ultimately, restrict access of the web service to authorized users, right? Very easy if you control the web service (if you don't -- wrap it in a web service which you do control).
1) Create a public/private key pair. The private key goes on the web service server, which is put in a dungeon and guarded by a dragon. The public key goes on the phone. If someone is able to read the public key, this is not a problem.
2) Have each copy of the application generate a unique identifier. How you do this is up to you. For example, you could build it into the executable on download (is this possible for iPhone apps)? You could use the phone's GUID, assuming they have a way of calculating one. You could also redo this per session if you really wanted.
3) Use the public key to encrypt "My unique identifier is $FOO and I approved this message". Submit that with every request to the web service.
4) The web service decrypts each request, bouncing any which don't contain a valid identifier. You can do as much or as little work as you want here: keep a whitelist/blacklist, monitor usage on a per-identifier basis and investigate suspicious behavior, etc.
5) Since the unique identifier now never gets sent over the wire, the only way to compromise it is to have physical access to the phone. If they have physical access to the phone, you lose control of any data anywhere on the phone. Always. Can't be helped. That is why we built the system such that compromising one phone never compromises more than one account.
6) Build business processes to accommodate the need to a) remove access from a user who is abusing it and b) restore access to a user whose phone has been physically compromised (this is going to be very, very infrequent unless the user is the adversary).
The simple answer is that as things stand today it's just not possible to keep secrets on the iPhone. A jailbroken iPhone is just a general-purpose computer that fits in your hand. There's no trusted platform hardware that you can access. The user can spoof anything you can imagine using to uniquely identify a given device. The user can inject code into your process to do things like inspect the keychain. (Search for MobileSubstrate to see what I mean.) Sorry, you're screwed.
One ray of light in this situation is in app purchase receipts. If you sell an item in your app using in app purchase you get a receipt that's crypto signed and can be verified with Apple on demand. Even though you can't keep the receipt secret it can be traced (by Apple, not you) to a specific purchase, which might discourage pirates from sharing them. You can also throttle access to your server on a per-receipt basis to prevent your server resources from being drained by pirates.
UAObfuscatedString could be a solution to your problem. From the docs:
When you write code that has a string constant in it, this string is saved in the binary in clear text. A hacker could potentially discover exploits or change the string to affect your app's behavior. UAObfuscatedString only ever stores single characters in the binary, then combines them at runtime to produce your string. It is highly unlikely that these single letters will be discoverable in the binary as they will be interjected at random places in the compiled code. Thus, they appear to be randomized code to anyone trying to extract strings.
If you can bear to be iPhone OS 3.0-only, you may want to look at push notifications. I can't go into the specifics, but you can deliver a payload to Apple's servers along with the notification itself. When they accept the alert (or if your app is running), then some part of your code is called and the keychain item is stored. At this point, that is the only route to securely storing a secret on an iPhone that I can think of.
I had the same question and spent a lot of time poking around for an answer. The issue is a chicken and egg one: how to pre-poluate the keychain with data needed by your app.
In any case, I found a technique that at least will make it harder for a jailbreaker to uncover the information - they'll at least have to disassemble your code to find out what you did to mask the info:
String Obfuscation (if the link breaks search for "Obfuscate / Encrypt a String (NSString)")
Essentially the string is obfuscated before placed in the app, then you unobfuscate it using code.
Its better than doing nothing.
David
EDIT: I actually used this in an app. I put a base coding string into the info.plist, then did several operations on it in code - rot13, rotate/invert bytes, etc. The final processed string was used to decode the obfuscated string. Now, the three letter agencies could for sure break this - but at a huge cost of many hours decoding the binary.
I was going to say that this is the best technique I've come across, but I just read Kiran's post on UAObfuscatedString (different answer), which is a completely different way to obfuscate. It has the benefit of no strings saved anywhere in the app - each letter is turned into a method call. The selectors will show up as strings, so a hacker can quickly tell that your class used that technique though.
I think that this similar question, and my answer, may be relevant to your case too. In a nutshell, there was some talk of a trusted platform module being present in an iPhone. This would allow your service to trust an iPhone, even in the hands of an attacker. However, it looks like using the keychain is your best bet.
Did you consider/try the Push Notification suggestion, for initially transmitting the secret to the app & keychain? Or end up finding some other method to achieve this?
I'm going have my iphone app upload images to Amazon S3. Instead of putting the AWS credentials in the app, I am going to have the app phone home to my server for the URI and headers to use in the S3 upload request. My server will generate the S3 URI, proper signatures, etc. I can then implement a tighter, more specific security model on my app's webservice than AWS offers by itself and not give away my AWS keys to anyone with a jailbroken iphone.
But there still has to be some trust (credentials or otherwise) given to the app, and that trust can be stolen. All you can ever do is limit the damage done if someone jailbreaks an iphone and steals whatever credentials are in the app. The more powerful those credentials are, the worst things are. Ways to limit the power of credentials include:
avoid global credentials. make them per-user/application
avoid permanent credentials. make them temporary if possible
avoid global permissions. give them only the permissions they need. for instance, write permissions might be broken down into insert, overwrite, delete, write against resource group A or B, etc, and read could be broken into read named resources, read a list of all existing resources, read resource groups A or B, etc.
I would recommend creating a key at run time if possible. This way if the key were to get apprehended during a particular session, once the session ends, the key will be worthless. They could still apprehend the key from memory if they are smart enough, but it wouldn't matter since the key would become invalid after a period of time.
Sounds wonky. Would use HTTPS and maybe an encryption package to handle the key.
I think CommonCrypto is available for iPhone.
EDIT: Still sounds wonky. Why would anyone pass a secret key in an HTTP header? Anyone who traces your network traffic (via a logging wifi router, for instance) would see it.
There are well-established security methods for encrypting message traffic...why not use them rather than invent what is basically a trivially flawed system?
EDIT II: Ah, I see. I would go ahead and use the Keychain...I think it is intended for just these kinds of cases. I missed that you were generating the request using the key. Would still use HTTPS if I could though, since that way you don't risk people deducing your keygeneration scheme via inspection of enough signatures.