Reply #175: It's really a cost issue, WRT NSA cores.

[boppers]

It's simply not worth the cost to brute force every AES 256 message... especially when folks like Assange can, in about half a minute, create an eternally unbreakable "message", tying up resources for years, by something as simple as a stream cypher, combined with other cyphers.

Hint: There's a reason the file is so freaking huge. Even if the stream cypher is broken (no mean feat), the message is still hidden in huge amounts of noise, so they have to test not only every stream key, but every additional possible additional algo on every single cypher result. Depending on paranoia levels, it may take multiple cyphers, times multiple cyphers, times complexity for each cypher.