I am using Bouncy Castle to generate a public/private keypair and using it for encryption tasks.
What would be the best way to store the keypair securely?
I have been unable to find a way to store on the devices keystore. Storing on a txt file wont work because it is as insecure as it gets. I could store it in RMS but then how does one secure this from a person with enough motivation to snoop?
Data store Update:
Problem with RMS is that if the application is saved in the mem card then the datastore is easily accessible to anyone.
As you're already using Bouncy Castle, then just implement a simple PBE (password based encryption) scheme to allow the records stored to be encrypted. For an example on how to do this have a look at the simple application I wrote many years ago.
http://www.eaves.org/jon/j2me/pocket.shtml
If you look at the .record package, you can see what I've done to encrypt and store individual records.
The "downside" to this approach is that you need to get the user to choose a "passphrase" and use that as part of the PBE. I'm not aware of any other approach to do what you want to do, and maintain security over the information stored. Any attempt to "hide" the key is futile, and insecure.
see my answer here, its secure to save in record store
How to sort recordstore records based on a certain field in it?
every application have its own record store and removed on application uninstall
Related
I'd like to use Windows.Security.Credentials.PasswordVault in my desktop app (WPF-based) to securely store a user's password. I managed to access this Windows 10 API using this MSDN article.
I did some experiments and it appears that any data written to PasswordVault from one desktop app (not a native UWP app) can be read from any other desktop app. Even packaging my desktop app with Desktop Bridge technology and thus having a Package Identity does not fix this vulnerability.
Any ideas how to fix that and be able storing the app's data secure from other apps?
UPDATE: It appeared that PasswordVault adds no extra security over DPAPI. The case is closed with a negative result.
(this is from what I can understand of your post)
There is no real way of preventing data access between desktop apps when using these kind of API's http://www.hanselman.com/blog/SavingAndRetrievingBrowserAndOtherPasswords.aspx tells more about it. You'd probably just want to decrypt your information.
memory access restriction is difficult, code executed by the user is always retrievable by the user so it would be difficult to restrict this.
have you considered using the Windows Data Protection API :
https://msdn.microsoft.com/en-us/library/ms995355.aspx
grabbed straight from the source
DPAPI is an easy-to-use service that will benefit developers who must provide protection for sensitive application data, such as passwords and private keys
WDPAPI uses keys generated by the operating system and Triple DES to encrypt/decrypt your data. Which means your application doesn't have to generate these keys, which is always nice.
You could also use the Rfc2898DeriveBytes class, this uses a pseudo-random number generator to decrypt your password. It's safer than most decrypters since there is no practical way to go back from the result back to the password. This is only really useful for verifying the input password and not retrieving it back again. I have never actually used this myself so I would not be able to help you.
https://msdn.microsoft.com/en-us/library/system.security.cryptography.rfc2898derivebytes(v=vs.110).aspx
see also this post which gives a way better explanation than I can.
How to securely save username/password (local)?
If I misunderstood the question in some way, tell me, I will try to update the answer.
NOTE that modern/metro apps do not have this problem, although they still are accessible in other ways.
The hard truth is that storing a password in a desktop application, 100% securely is simply not possible. However, you can get close to 100%.
Regarding your original approach, PasswordVault uses the Credential Locker service which is built into windows to securely store data. Credential Locker is bound to the user's profile. Therefore, storing your data via PasswordVault is essentially equivalent to the master password approach to protecting data, which I talk about in detail further down. Only difference is that the master password in that case is the user's credentials. This allows applications running during the user's session to access the data.
Note: To be clear, I'm strictly talking about storing it in a way that allows you access to the plain text. That is to say, storing it in an encrypted database of any sort, or encrypting it yourself and storing the ciphertext somewhere. This kind of functionality is necessary in programs like password managers, but not in programs that just require some sort of authentication. If this is not a necessity then I strongly recommend hashing the password, ideally per the instructions laid out in this answer by zaph. (Some more information in this excellent post by Thomas Pornin).
If it is a necessity, things get a bit more complicated: If you want to prevent other programs (or users I suppose) from being able to view the plaintext password, then your only real option is to encrypt it. Storing the ciphertext within PasswordVault is optional since, if you use good encryption, your only weak point is someone discovering your key. Therefore the ciphertext itself can be stored anywhere. That brings us to the key itself.
Depending on how many passwords you're actually trying to store for each program instance, you might not have to worry about generating and securely storing a key at all. If you want to store multiple passwords, then you can simply ask the user to input one master password, perform some salting and hashing on that, and use the result as the encryption key for all other passwords. When it is time for decryption, then ask the user to input it again. If you are storing multiple passwords then I strongly urge you to go with this approach. It is the most secure approach possible. For the rest of my post however, I will roll with the assumption that this is not a viable option.
First off I urge you not to have the same key for every installation. Create a new one for every instance of your program, based on securely generated random data. Resist the temptation to "avoid having to store the key" by having it be generated on the fly every time it is needed, based on information about the system. That is just as secure as hardcoding string superSecretKey = "12345"; into your program. It won't take attackers long to figure out the process.
Now, storing it is the real tricky part. A general rule of infosec is the following:
Nothing is secure once you have physical access
So, ideally, nobody would. Storing the encryption keys on a properly secured remote server minimizes the chances of it being recovered by attackers. Entire books have been written regarding server-side security, so I will not discuss this here.
Another good option is to use an HSM (Hardware Security Module). These nifty little devices are built for the job. Accessing the keys stored in an HSM is pretty much impossible. However, this option is only viable if you know for sure that every user's computer has one of these, such as in an enterprise environment.
.Net provides a solution of sorts, via the configuration system. You can store your key in an encrypted section of your app.config. This is often used for protecting connection strings. There are plenty of resources out there on how to do this. I recommend this fantastic blog post, which will tell you most of what you need to know.
The reason I said earlier not to go with simply generating the key on the fly is because, like storing it as a variable in your code, you rely exclusively on obfuscation to keep it secure. The thing about this approach is that it usually doesn't. However, sometimes you have no other option. Enter White Box cryptography.
White box cryptography is essentially obfuscation taken to the extreme. It is meant to be effective even in a white-box scenario, where the attacker both has access to and can modify the bytecode. It is the epitome of security through obscurity. As opposed to mere constant hiding (infosec speak for the string superSecretKey approach) or generating the key when it is needed, white box cryptography essentially relies on generating the cipher itself on the fly.
Entire papers have been written on it, It is difficult to pull off writing a proper implementation, and your mileage may vary. You should only consider this if you really really really want to do this as securely as possible.
Obfuscation however is still obfuscation. All it can really do is slow the attackers down. The final solution I have to offer might seem backwards, but it works: Do not hide the encryption key digitally. Hide it physically. Have the user insert a usb drive when it is time for encryption, (securely) generate a random key, then write it to the usb drive. Then, whenever it is time for decryption, the user only has to put the drive back in, and your program reads the key off that.
This is a bit similar to the master password approach, in that it leaves it up to the user to keep the key safe. However, it has some notable advantages. For instance, this approach allows for a massive encryption key. A key that can fit in a mere 1 megabyte file can take literally billions of years to break via a brute force attack. Plus, if the key ever gets discovered, the user has only themselves to blame.
In summary, see if you can avoid having to store an encryption key. If you can't, avoid storing it locally at all costs. Otherwise, your only option is to make it as hard for hackers to figure it out as possible. No matter how you choose to do that, make sure that every key is different, so even if attackers do find one, the other users' keys are safe.
Only alternative is to encrypt password with your own private key stored somewhere in your code. (Someone can easily disassemble your code and get the key) and then store encrypted password inside PasswordVault, however the only security you have is any app will not have access to password.
This is dual security, in case of compromised machines, attacker can get access to PasswordVault but not your password as they will need one more private key to decrypt the password and that will be hidden somewhere in your code.
To make it more secure, if you leave your private key on your server and expose an API to encrypt and decrypt password before storing in Vault, will make it most secure. I think this is the reason people have moved on to OAuth (storing OAuth token in PasswordVault) etc rather then storing password in vault.
Ideally, I would recommend not storing password, instead get some token from server and save it and use that token for authentication. And store that token in PasswordVault.
It is always possible to push the security, with miscellaneous encryption and storage strategies. Making something harder is only making the data retrieval longer, never impossible. Hence you need to consider the most appropriate level of protection considering execution cost x time (human and machine) and development cost x time aspects.
If I consider strictly your request, I would simply add a layer (class, interface) to cipher your passwords. Best with asymmetrical encryption (and not RSA). Supposing the other softs are not accessing your program data (program, files OR process), this is sufficient. You can use SSH.NET (https://github.com/sshnet/SSH.NET) to achieve this quickly.
If you would like to push the security and give a certain level of protection against binary reverse-engineering (including the private key retrieval), I recommend a small (process limited) encrypted VM (like Docker, https://blogs.msdn.microsoft.com/mvpawardprogram/2015/12/15/getting-started-with-net-and-docker/) based solution such as Denuvo (https://www.denuvo.com/). The encryption is unique per customer and machine based. You'll have to encapsulated you c# program into a c/c++ program (which acts like a container) that will do all the in-memory ciphering-deciphering.
You can implement your own strategy, depending on the kind of investment and warranty you require.
In case your program is a backend program, you can pick the best strategy (the only I really recommend) of all which is to store the private key at the client side, public key at backend side and have local deciphering, all transmitted password would be hence encrypted. I would like to remark that password and keys are actually different strategies to achieve the same goal: checking if the program talks to the right person without knowing the person's identity; I mean this: instead of storing passwords, better store directly public keys.
Revisiting this rather helpful issue and adding a bit of additional information which might be helpful.
My task was to extend a Win32 application that uses passwords to authenticate with an online service with a "save password" functionality. The idea was to protect the password using Windows Hello (UserConsentVerifier). I was under the impression that Windows surely has something comparable to the macOS keychain.
If you use the Windows Credential Manager APIs (CredReadA, CredWriteA), another application can simply enumerate the credentials and if it knows what to look for (the target name), it will be able to read the credential.
I also explored using DPAPI where you are in charge of storing the encrypted blob yourself, typically in a file. Again, there seems to be no way (except obfuscation) to prevent another application from finding and reading that file. Supplying additional entropy to CryptProtectData and CryptUnprotectData again poses the question of where to store the entropy (typically I assume it would be hard-coded and perhaps obfuscated in the application: this is security by obscurity).
As it turns out, neither DPAPI (CryptProtectData, CryptUnprotectData) nor Windows Credential Manager APIs (CredRead, CredWrite) can prevent another application running under the same user from reading a secret.
What I was actually looking for was something like the macOS keychain, which allows applications to store secrets, define ACLs on those secrets, enforce biometric authentication on accessing the secret, and critically, prevents other applications from reading the secrets.
As it turns out, Windows has a PasswordVault which claims to isolate apps from each other, but its only available to UWP apps:
Represents a Credential Locker of credentials. The contents of the locker are specific to the app or service. Apps and services don't have access to credentials associated with other apps or services.
Is there a way for a Win32 Desktop application to access this functionality? I realize that if a user can be brought to install and run a random app, that app could probably mimic the original application and just prompt the user to enter the secret, but still, it's a little disappointing that there is no app-level separation by default.
I'm working on a web platform which will contain some rather sensitive personal information, and obviously this raises the problematic of how secure this data will be. Users can upload some files, and I was wondering what the best way was to store them securely.
I've done several searches, and one of the pages which I found quite useful was https://stormpath.com/blog/how-to-gracefully-store-user-files (I'm not using Stormpath btw, just looking for implementation ideas) which said that using Cloud services is one of the best solutions as their security is already quite tight. The caveat I've found in other discussions is that your data is stored by a third-party, and if you use Amazon-managed encryption keys, they can theoretically view your data.
Yet, overall, one thing I don't quite understand - I guess because of my total lack of expertise in the domain - is why storing files elsewhere than on your own server would be more secure. I've tried imagining a few different scenarios :
1- files stored on the webserver with no encryption
-> obvious issue if someone breaks into the server
2- files stored on the webserver, encrypted with a global key, stored outside of the "public" folder
-> if someone manages to get access to the server, they could get the files but also find the encryption key (and whatever they want actually) and access the files?
3- files stored on a 3rd party cloud provider, ewith a global key, stored outside of the "public" folder
-> well.. same issue? if someone gets access to the server, they can get the encryption key, and I guess it wouldn't be difficult for them to get the file which gives the credentials to the cloud account, and hence get the files?
Overall, it seems that whenever your web server gets compromised.. your data is basically compromised as well? The only solution would be to encrypt the files with a key only known to the user, but in practice this comes with a lot of "usability" cons : data irrecoverable if the user forgets the key, user needs to keep safe a long encryption key on top of his password, etc..
Any comments to shed some light on this topic for me?
Thanks very much
I am considering encryption options for a new Sybase project. I am thinking that Sybase encryption is the wrong strategy because a) dba's can get in, and b) if and when we migrate to SQL Server or Oracle I don't want to deal with different encryption strategies.
Therefore I'm thinking to encrypt the sensitive data (symmetric encryption) in my Java code before storing it in the DB.
Now, the encrypted fields better not have their encryption key changed, ever, except in a very controlled environment, which for me effectively means never. So it's going to be a permanent password.
The question is, where should I keep this password in a way that it is accessible from the program but not accessible to anyone else. If it's in a properties file, any developer with access to our Git repo could see it.
We could hard code it in the source code, but good lawd, that's a bad practice.
We could generate it in source, like the 10th Fibonacci or 3!+8! that would be hard to locate, but it's still rather exposed.
We could have the sa's maintain it in the environment, but then where do they file it for future reference?
So many poor choices. Are there any good ones?
Simply using some secret code to create the key on the fly is both an insecure method and produces a poor key. The DB keep needs to be a random byte array. Keep in mind that the key needs to be in memory when used which will be most of the time for the DB.
WRT using the DB encryption, examine closely if the algorithm is fully specified and compatibility to another DB. There is also the possibility that the entire DB will need to be run-off and then added to a new DB, in that case using the internal DB encryption will be transparent.
You really need to consider needing to be able to change the encryption key in the future, what will you do if it is ever compromised? There are solutions to this dilemma. There may be a substantial performance penalty performing the encryption outside the DB, there is a substantial setup time for each new encryption operation. Also since not all columns will be encrypted (a good guess) that information is not shared by the DB and the outside encryption code, that coupling is not good for design nor maintenance.
Do not connect the DB server to the Internet, make it separate and connected with a non-networked connection such as direct Ethernet. This also limited the number of admin users of the only system that contains the encryption key.
Another important part of the solution is to restrict admin access to the server. This includes requiring two-factor authentication as well as severely limiting the number of administrators. You need to control the second-factor to physical serial-numbered devices owned by the organization so that they can be positively retrieved on personnel changes and not copied. Personally I favor RSA SecureID (or similar) hardware devices, there is positive control.
Finally in answer to the question, keep the key in a file on the DB server secured as above, that is with no Internet access and restricted admin access.
I am developing standalone app for cross platform using electron.
I want store private data like private key, private data for some
execution in app. Execution like encrypt / decrypt data.
Or
I want store some secured information like user password, proprietary
data on app
Are any possible way to store these kind of secure information and app user unable to get any way?
There is an NPM module made for Atom editor (the app Electron was made for) called Keytar. It uses the native OS APIs for secure storage. eg. The keychain on OS X.
https://github.com/atom/node-keytar
I don't know the specific technology that you are using, so my answer will point in general to the key storage issue.
First, two big remarks:
Even with some heavy specialized hardware (banks and other critical systems use Hardware Security Modules -HSMs- for this), there is always a risk of getting your key stolen. What you choose to do depends on how important is your key and how much are you willing to do to protect it. I will try to avoid to mention solutions involving hardware, because they are usually overkill for most people.
There are, however, good practices that you can follow: https://www.owasp.org/index.php/Cryptographic_Storage_Cheat_Sheet
Now, some advise. Whatever you do, don't store your key in plaintext (and much less hardcoded). If you are using public key cryptography, PKCS12 files (usually with extension .p12 or .pfx) are the standard way to store the data. They are usually password protected.
Here you face a problem: if you have a key, you need to use it. If you use the key, it will be in "plaintext", at least in RAM. So, you need a way to enable the access that keeps the key as isolated as possible. If the actions are triggered by a user, things are relatively nice, because you could ask for the password before using the key.
If the actions are automated, however, you need to find a way to store the password. Even security software like some PGP implementations have approaches for this that aren't nice:
Ask for the password in command line: command -password my-password. This, put in a bat, works. But the password is stored and, depending of the operating system, even available with the command history.
Store it in a file: at least you don't leave copies around, but the password is still in plaintext.
Encrypt it using system data as encryption key: the password is relatively protected, but you lose portability and an attacker with access to the computer won't be stopped by the control.
Ask for the password once one the service is on: a bit more reasonable, but not always possible (if the service is critical but just one person has the password, availability might be compromised).
Fancy things could be done with threshold decryption, but that's probably too much for that case also.
I do not provide details on each option because what you can do probably depends on what your framework allows and the way in which your system is used, but I hope it helps as a reference of the different options. In any case, do not implement any cryptographic functionality on your own. Bad crypto is worse than no crypto at all.
Avoid storing private or server-side details like a private key in an electron app. Electron app's data and file can be accessed from the app.asar file and electron do not protect the content at all. There is no such mechanism of code protection in electron. However NW.js supports source code protection, You can read it here. So according to me, it's not safe to store private accreditations like signing a certificate or private key in electron source code.
As another way, you can store these data using node-keytar in the keychain for mac, the credential manager in windows and Gnom Keyring in Linux using native api. But still, these credentials are accessible to the user and does not make sense to storing private tokens (i.e. Token for GitHub private repository having administrative rights). It depends upon the user, If he/she is sophisticated enough to understand what did you stored in Keychain, Credential Manager or Keyring, they can misuse it or can use against you. So the final answer is,
Do not store Credentials/Private key or Administrative Tokens in electron source or using node-keytar.
the perfect way of storing data in electron is this package: https://www.npmjs.com/package/electron-data-holder
this package stores data in a JSON file but it gives you the ability to encrypt the data.
read more in the documentation
I'm working on a small project that stores an encrypted password, using code from Simple insecure two-way "obfuscation" for C#. The password will be stored locally on the user's PC, and there is no database involved to store a second key.
I will need to share this code up to my team and, eventually, possibly to other teams. Since it's 2-way encryption, I don't want the key/vector information to be shared, and anyone be able to access the passwords generated with that key/vector.
I thought about using some mishmash of machine name/user SID to generate the key/vector on a per machine/user basis, but it would be easy enough to get that information if you wanted it.
I thought about having the user generate a random key to start with, but hey, you have to store that somewhere, too.
Am I thinking too complicated about this?
What are your suggestions to do this the most securely?