Earlier quoted context omitted.
tarsnap
I'm guessing tarsnap doesn't satisfy the 3rd criteria, nor is tarsnap able to decrypt the user's files, even when the client is connected. Perhaps cperciva can comment.
Yes, exactly.
Dropbox Lack of Security
91–100 of 193 posts
Re: Dropbox Lack of Security
#92Earlier quoted context omitted.
Isn't one of the major cool things about dropbox that if your computer hard drive gets smashed (and thus the key is destroyed), you can still access your files somewhere else?
That's why you should always keep backups of your key somewhere. Even on paper in a safe deposit box.
We are talking here about Dropbox being simple to use for everyone and you start talking about keeping backups of keys. In safe deposit boxes, no less. Wow.
Re: Dropbox Lack of Security
#93I don't know if that's how dropbox does it, but I could imagine that they have a master key to which normal employees don't have access, you need the founder and a trusted second person to retrieve it.
Thus their statement "Dropbox employees aren't able to access user files, and when troubleshooting an account" wouldn't be too far off the mark, and they can still make the data available to the government, on request and with higher effort.
Re: Dropbox Lack of Security
#94forgive me if I'm naive, but can file hashes be spoofed in any way? I'm thinking upload a bunch of files that hash to random numbers, then download the de-duplicated original files. could someone more knowledgable in this area tell me if this is a credible threat?
and is the hashing done by the client, or server-side? because client-side would make spoofing even easier.
Spoofing is the easy thing, as the hashing is done in the client. You'd just have to figure out the protocol to get the file with a known hash (and other metadata, probably).
However, "guessing" the hash for a file that you don't have is not. The chance that you'll get a file by trying random hashes is very very very small.
Re: Dropbox Lack of Security
#95This is the first time I've heard someone on HN actually ask for more security theatre. Sure, Dropbox could spend seven figures to get a ISOxxxx whatever consultancy to draw up a 125 page document describing their internal checks, do the obligatory all-hands yearly mandatory training where you have to get 10/10 questions right and question 1 is "A user has uploaded naked pictures of themselves to their account. True…
That's a severe oversimplification, IMO. Just recently there was news that duplicating the host_id from the Dropbox config onto another system will immediately gain access to all of the Dropbox files associated with that host_id, without further authentication. It's not security theatre to acknowledge that the security in such a system could be improved, especially as an option for those that require it. #3 could eas…
duplicating the host_id from the Dropbox config onto another system will immediately gain access to all of the Dropbox files associated with that host_id, without further authentication
Sounds like the host_id is the secret key. So to paraphrase: "If you type someone's username & password into the facebook login page, you get complete access to their account"
Re: Dropbox Lack of Security
#96Earlier quoted context omitted.
When you forget your password you'll lose access to all of your data. Password recovery won't be possible if the key is password protected.
I believe most tech users understand that and accept the compromise when they are using an 'encrypted' system
But Dropbox isn't aimed at tech users.
Re: Dropbox Lack of Security
#97Earlier quoted context omitted.
You generate the key from your username and password and/or store it locally?
function decrypt(cipertext, key) { var req = new XMLHttpRequest(); req.open("POST", "/retrieve_user_key?key="+key); req.send(); // decryption routines return result; } Do you trust Dropbox to not send compromised JavaScript every time? If so, why not trust them with your keys in the first place? Of course you also need to trust the desktop Dropbox client. The only (approximately) truly secure way to do this is with a…
Reminds me of the Underhanded C Contest, the goal is write a C programme that appears innocent when someone examines the source code, but actually has an intentional malicous action (e.g. stores user data)
Re: Dropbox Lack of Security
#98hi there, arash from dropbox here. all data is (as we state in the referenced help article) encrypted before it's stored on the backend. all data on dropbox can be made shareable and is web viewable. as a consequence, we do need the ability to decrypt in the cloud. re. employee access to files - there are controls to prevent this. for example, even drew (founder/CEO), doesn't have physical access to our storage serve…
A point of feedback: I know it is illegal for you to inform users if you have received a warrant for their data, but you should devise a method where a flag such as 'third party access' is set in the user preference panel to let them know that somebody has accessed the data
architect this flag as part of any 'admin' access and describe it on your website - users would feel better about it
if the feds know your system is designed in a way that you can't help but to inform users that data has been accessed, it might dissuade them from approaching you with warrants in the first place
Re: Dropbox Lack of Security
#99hi there, arash from dropbox here. all data is (as we state in the referenced help article) encrypted before it's stored on the backend. all data on dropbox can be made shareable and is web viewable. as a consequence, we do need the ability to decrypt in the cloud. re. employee access to files - there are controls to prevent this. for example, even drew (founder/CEO), doesn't have physical access to our storage serve…
A point of feedback: I know it is illegal for you to inform users if you have received a warrant for their data, but you should devise a method where a flag such as 'third party access' is set in the user preference panel to let them know that somebody has accessed the data architect this flag as part of any 'admin' access and describe it on your website - users would feel better about it if the feds know your system…
Interesting technical idea, but it ignores how power works.
The govt will just request that they change the code so that you're in compliance.
Re: Dropbox Lack of Security
#100Earlier quoted context omitted.
A point of feedback: I know it is illegal for you to inform users if you have received a warrant for their data, but you should devise a method where a flag such as 'third party access' is set in the user preference panel to let them know that somebody has accessed the data architect this flag as part of any 'admin' access and describe it on your website - users would feel better about it if the feds know your system…
Interesting technical idea, but it ignores how power works. The govt will just request that they change the code so that you're in compliance.
I poured through the laws and talked to a lawyer about it, though this was years ago. It is illegal to inform a user directly in any way, they can't make you re-architect your system to provide them a backdoor unknown to the user.
also the wording can not mention 'warrant' or 'fbi' so it has to be something like 'third party access'
I have been meaning to do this as a 'project' with full legal advice etc. and suggest it to google, other cloud providers
Edit: found that rsync.net already do this, in a different way, as a warrant canary: http://www.rsync.net/resources/notices/canary.txt