meta user
network profile
|
Oct 1 |
comment |
Is Convergent Encryption really secure? The second attack, which we call "learn the remaining information", is not so obvious, and as far as I know nobody was aware of this attack until 2008 when Drew Perttula and Brian Warner developed it as an attack against the Tahoe-LAFS secure filesystem. In the "learn the remaining information" attack, the attacker can make guesses about a few secret, random, unknown parts of a larger file and then find out if one of their guesses is correct. Please see the write-up at: tahoe-lafs.org/hacktahoelafs/drew_perttula.html |
|
Oct 1 |
comment |
Is Convergent Encryption really secure? There are two possible attacks. The first one, which we call the "confirmation of a file attack" is the obvious problem that deduplication exposes the fact that the two things were the same as each other. This issue was immediately appreciated and discussed when convergent encryption was first proposed (not under that name) on the cypherpunks mailing list in 1996. (Before Microsoft applied for a patent on convergent encryption, so the cypherpunks discussion is prior art that invalidates the Microsoft patent.) |
|
Oct 1 |
comment |
Is Convergent Encryption really secure? I was asked over on the security stack exchange (security.stackexchange.com/questions/7142/… ) to explain more about this. |
|
Sep 6 |
comment |
How can we reason about the cryptographic capabilities of code-breaking agencies like the NSA or GCHQ? Don't focus too much on specific organizations, such as the American National Security Agency (NSA). Maybe you think NSA are The Good Guys and will not do anything bad (even if they have such an ability) or you at least think they are on your side and will not do anything bad to you. But do we have any reason to believe that the Chinese or Russian classified cryptography research are less advanced than the American or British? Also some users (e.g. Europeans) may not feel okay about the possibility of NSA having such power over their communications. |
|
Sep 1 |
comment |
How can we reason about the cryptographic capabilities of code-breaking agencies like the NSA or GCHQ? Yes, this is a good question. Everyone should have this question. The fact that nobody has a good answer is an important fact and it is good to publish the question on this site. A lot of the most important questions around don't really have solid answers. Uncertainty and ignorance are what we have to face up to and decide how to manage. |
