I have a question on the limitations of cryptography. May seem like a stupid question. I apologise in advance.
This is for a client which I myself am trying to wrap my head around it.
The information will be encrypted and then encoded in an accessible format e.g. QR or barcode. Decryption is using the application our developers are creating. The problem is that the application would be offline majority of the time when it is in used as the users would be in areas that have either intermittent or poor reception. So to be able to decrypt it, the application has to have the private key present on the device itself, correct? Would this even be a good solution? Even the developers have concerns on having all the apps offline with the same private key present. Note that the application will be used by multiple groups.
Is there an alternative that I can explore that any of you can suggest where we don't have to store the private key but still manage to secure the information for offline use? So far I've look into DRM for restricting copying information but not sure how it would help. I'm also willing to look into other solutions for this.
The database holding the information would be updated when they have an internet connection. I'm only assuming on this part since I'm not handling this part of the project.
Please and thank you in advance for your advice.
Maybe not the right way but found a suitable path.
Using a combination of asymmetric key and symmetric key where the symmetric key is used to decrypt data on the offline device. Asymmetric is used to encrypt the data. The asymmetric keys is only exchange when the devices are in need to be sync'd. This would put the trust on the devices itself so I'm not worried on this.
This idea came from Sectigo - Why Automotive Key Fob Encryption Hacks Are Making Headlines?
Related
I am working for a big consulting firm and we have a platform that exchanges data with couple of big companies. We are trying to enhance then platform on which enterprises will be able to deposit data. The workflow that we are building is that we would like the companies to upload data on the platform, without us knowing who uploaded the data (the reason why: we do not need to every-time sign a complicated NDA).
I had a look at couple of cryptographic systems, I thought of Asymmetric Encryption, but then you need to know the owner's public key in order to decrypt the message.
I also thought of Zero Knowledge Proof, but then again you need to know the identity of the data'owner.
I thought even at merkle tree in order to whitelist specific public key that can access the platform, but then again you need to know the public key's owner.
So any idea, how I can give access to specific users to a platform, without knowing who after that accesses it? Thanks for your help, am a bit stuck.
I'm working on a project with some sensitive data. I'm trying to do statistics about Facebook conversation with a client only website. Until now, I have a big JSON file of a Facebook conversation that I parse and do stuff with data. I want to be able to deliver this file only to my friends. So, what I thought is that I locally encrypt it (with I don't know yet which algo), deliver the encrypted file and give the password to my friend so only them can decrypt it. Do you think it will work and it will be secure enought ? I don't want someone to be able to bruteforce it or whatever, as it is private conversation. And do you have any recommendation about the algo I should use ?
You placed an abstract question so you may get only an abstract answer
deliver the encrypted file and give the password to my friend so only them can decrypt it. Do you think it will work and it will be secure enought ?
There are a few conditions to make encryption safe.
using any modern cipher which is not considered weak (e.g. AES-128 provides enough of security)
the encryption key is random (or password used to generate the key is long and random enough)
optionally you may add an authentication tag to ensure message integrity
And do you have any recommendation about the algo I should use ?
To encrypt data itself, any current modern cipher will do, e. g. aes, 3des,...
If you don't want to dive into security and you just want to encrypt a file, you can you some out of box tools which would do that for you. Try to look at openssl, pgp, gpg or nppcrypt (plugin for notepad++). Just make the password long and random.
The question is how do you get the key or password to your friend safely. You can either use different channel or using asynchronous (such as RSA or ECC). You can search, read, try out and ask more specific question
For our messaging app, if we send user messages directly to CloudKit (without doing any of our own encryption), can we claim that our app is end-to-end encrypted, "where only the communicating users can read the messages"?
Matt,
I presume/assume this is a coding question? So I'll answer with a coded answer :)
You can offer your guarantee that messages are only readable by communicating users by encrypting the messages using public/private key pairs. Technology that has been around for more than a while now. This discussion talks in detail about the process.
Search for "Swift RSA Public Key Encryption Howto" on https://forums.developer.apple.com forum.
I know this is an old and somewhat controversial question, but I thought I'd lend my two cents on the subject.
After some quick Googling, the most authoritative public and user-facing answer to this question I've found is on Apple's Privacy page. See the section on iCloud, which reads,
Your iCloud content [...] is encrypted when it’s transferred and when it’s stored on our servers.
It then talks about CloudKit.
That sounds pretty end-to-end-ish to me.
However, they go on to state that "some personal data, such as Home and Health data, is stored with end-to-end encryption." This contrasting passage does not bode well for your "We're end-to-end encrypted!" requirement, unless the quote above suffices for your purposes.
For my own present project, it does, as my data isn't necessarily business-class levels of sensitive; I don't need full control over what and how everything is encrypted. My biggest concern is that I, the developer, cannot see my users' data. This, CloudKit enforces for me, whereas tools like Firebase do not.
That is all.
Happy Googling! 😊
I want to handle some confidential data in one of my web application. So that the data shouldn't able to read by the Developer or Database administrator.
We can easily hide the data from DB administrator by implementing some encryption technique. But still the developer can see the data since he only creating the decryption technique. I want only the end user should see his data.
I can't encrypt data using some algorithms like PBKDF2 or DB side encryption methods Like TDE & EKM because still I need to keep the encryption key somewhere. If I keep in server side or in db the developer can access and decrypt the data. If I keep it in client side, the user can't access the information from a separate machine.
So How to handle this situation? Thanks in advance.
You are heading the direction of Zero Knowledge Web Applications, such as implemented by SpiderOak (see also crypton). These applications typically work by deriving a key from the user's password using something like PBKDF2, and performing encryption/decryption on client side. However, there are a number of complexities to overcome to make it true zero-knowledge, and also to meet usability requirements. One could write an essay on this, but instead I suggest you start by reading the linked references. If you have any questions, let me know.
In a nutshell, the "more zero-knowledge" you want the system to be, the harder it is to realise without sacrificing usability (one example is overcoming the points made in Javascript Cryptography Considered Harmful). However, there are various tradeoffs you can make in order to make it sufficiently difficult to cheat without affecting usability too much.
I need to keep the encryption key somewhere
No you don't. The user only has to remember it. For convenience you could save it in the browser's local storage.
Some web applications, like Google Docs, store data generated by the users. Data that can only be read by its owner. Or maybe not?
As far as I know, this data is stored as is in a remote database. So, if anybody with enough privileges in the remote system (a sysadmin, for instance) can lurk my data, my privacy could get compromised.
What could be the best solution to store this data encrypted in a remote database and that only the data's owner could decrypt it? How to make this process transparent to the user? (You can't use the user's password as the key to encrypt his data, because you shouldn't know his password).
If encryption/decryption is performed on the server, there is no way you can make sure that the cleartext is not dumped somewhere in some log file or the like.
You need to do the encryption/decryption inside the browser using JavaScript/Java/ActiveX or whatever. As a user, you need to trust the client-side of the web service not to send back the info unencrypted to the server.
Carl
I think Carl, nailed it on the head, but I wanted to say that with any website, if you are providing it any confidential/personal/privileged information then you have to have a certain level of trust, and it is the responsibility of the service provider to establish this trust. This is one of those questions that has been asked many times, across the internet since it's inception, and it will only continue to grow until we all have our own SSL certs encoded on our fingerprint, and even then we will have to ask the question 'How do I know that the finger is still attached to the user?'.
Well, I'd consider a process similar to Amazons AWS. You authenticate with a private password that is not saved remotely. Just a hash is used to validate the user. Then you generate a certificate with one of the main and long-tested algorithms and provide this from a secure page. Then a public/private key algorithm can be used to encrypt things for the users.
But the main problem remains the same: If someone with enough privileges can access the data (say: hacked your server), you're lost. Given enough time and power, everything could be breaked. It's just a matter of time.
But I think algorithms and applications like GPG/PGP and similar are very well known and can be implemented in a way that secure web applications - and keep the usability at a score that the average user can handle.
edit I want to catch up with #Carl and Unkwntech and add their statement: If you don't trust the site itself, don't give private data away. That's even before someone hacks their servers... ;-)
Auron asked: How do you generate a key for the client to encrypt/decrypt the data? Where do you store this key?
Well, the key is usually derived from some password the user has chosen. You don't store it, you trust the user to remember it. What you can store is maybe some salt value associated to that user, to increase security against rainbow-table attacks for instance.
Crypto is hard to get right ;-) I would recommend to look at the source code for AxCrypt and for Xecrets' off-line client.
Carl
No, you can't use passwords, but you could use password hashes. However, Google Docs are all about sharing, so such a method would require storing a copy of the document for each user.