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I think the government also realized that for the majority of communications, truly strong cryptography is pretty useless. There is always a point where the in
by cube13 15y ago
I think the government also realized that for the majority of communications, truly strong cryptography is pretty useless. There is always a point where the information is basically worthless to keep secret.
For example, if the president(or other high ranking official) is making a "secret" visit, that information only needs to be kept encrypted for fairly short amount of time(maybe a week or so), which means that a less secure algorithm that takes a few weeks to crack is enough to encrypt the information. That way, even if an enemy gets the information and cracks it, it's useless when they finally read it.
For things that may need to stay secret for longer periods of time, like intelligence reports with the names of informants or long-term defense strategy plans, a stronger encryption method would be needed.
- tptacek 15y agoI have no insight into the NSA's capabilities; I've heard murblings that their practical edge is in knowing classes of implementation flaws that we don't, and in having decades of experience weaponizing those flaws... but for all we know, they have some algebraic structure attack on AES that makes it trivial to break. However, bear in mind that there's a real dollars-and-cents value to obscurity in cryptography when you're the NSA. When you're the NSA, you know your custom undocumented algorithm isn't trivially breakable (unlike virtually all bespoke commercial ciphers, which end up getting solved by SAT solvers as an exercise). Forcing your adversary to cryptanalyze an entirely new cipher imposes real and severe costs on them. That alone is a huge motivation to keep their own capabilities secret, and to not use standard algorithms to protect their own secrets --- even if, for all they know, those algorithms are sound.